all-in-one privacy solution":["Proton Unlimited est une solution tout-en-un respectueuse de la vie privée"],"Black Friday":["Black Friday"],"No ads. Privacy by default.":["Aucune publicité, le respect de la vie privée comme règle absolue"],"People before profits":["Les individus passent avant les profits"],"Security through transparency":["Notre engagement de transparence"],"The best Proton Mail ${ BLACK_FRIDAY } deals":["Les meilleures offres ${ BLACK_FRIDAY } de Proton Mail"],"The world’s only community- supported email service":["La seule messagerie au monde soutenue par la communauté"]},"specialoffer:limited":{"${ hours } hour":["${ hours } heure","${ hours } heures"],"${ hoursLeft }, ${ minutesLeft } and ${ secondsLeft } left":["Temps restant : ${ hoursLeft }, ${ minutesLeft }, ${ secondsLeft }"],"${ minutes } minute":["${ minutes } minute","${ minutes } minutes"],"${ seconds } second":["${ seconds } seconde","${ seconds } secondes"],"Limited time offer":["Offre à durée limitée"]},"specialoffer:listitem":{"Create multiple addresses":["Créez plusieurs adresses"],"Hide-my-email aliases":["Alias « hide-my-email »"],"Quickly unsubscribe from newsletters":["Désabonnez-vous rapidement des newsletters"],"Use your own domain name":["Utilisez votre propre nom de domaine"]},"specialoffer:logos":{"As featured in":["Ils en parlent"]},"specialoffer:metadescription":{"Get an encrypted email that protects your privacy":["Choisissez une messagerie électronique chiffrée qui protège votre vie privée"]},"specialoffer:metatitle":{"Proton Mail Black Friday Sale - Up to 40% off":["Offre Proton Mail Black Friday - Jusqu'à 40 % de réduction"]},"specialoffer:newmetadescription":{"Get up to 40% off Proton Mail subscriptions this Black Friday. Find great deals on our secure end-to-end encrypted email plans.":["Obtenez jusqu'à 40 % de réduction sur les abonnements Proton Mail à l'occasion du Black Friday. Profitez d'offres exceptionnelles sur nos abonnements de messagerie électronique sécurisée et chiffrée de bout en bout."]},"specialoffer:newmetatitle":{"Proton Mail Black Friday sale | Up to 40% off secure email":["Offre Black Friday Proton Mail | Jusqu'à 40 % de réduction"]},"specialoffer:note":{"* Billed at ${ TOTAL_SUM } for the first year":["* Facturé ${ TOTAL_SUM } pour la première année"],"*Billed at ${ TOTAL_SUM } for the first 2 years":["*Facturé ${ TOTAL_SUM } pour les 2 premières années"],"30-day money-back guarantee":["Garantie satisfait ou remboursé pendant 30 jours"],"Billed at ${ TOTAL_SUM } for the first 2 years":["Facturé ${ TOTAL_SUM } pour les 2 premières années"],"Billed at ${ TOTAL_SUM } for the first year":["Facturé ${ TOTAL_SUM } pour la première année"],"You save ${ SAVE_SUM }":["Vous économisez ${ SAVE_SUM }"]},"specialoffer:off":{"${ DISCOUNT } off":["-${ DISCOUNT }"],"${ PERCENT_OFF } off":["-${ PERCENT_OFF }"]},"specialoffer:testimonial":{"I love my ProtonMail":["J'adore mon ProtonMail"],"My favorite email service":["Ma messagerie électronique préférée"],"Thanks Proton for keeping us all safe in the complicated internet universe.":["Merci Proton de nous garder en sécurité dans l'univers complexe d'internet."],"You get what you pay for. In the case of big tech, if you pay nothing, you get used. I quit using Gmail and switched to @ProtonMail":["Vous avez ce pour quoi vous payez. Avec les Big Tech, si vous ne payez rien, vous êtes utilisé. J'ai arrêté d'utiliser Gmail et je suis passée @ProtonMail"]},"specialoffer:time":{"Days":["Jours"],"Hours":["Heures"],"Min":["Min"]},"specialoffer:title":{"And much more":["Avec en plus"],"Make your inbox yours":["Votre boite de réception sur mesure"],"Safe from trackers":["À l'abri des traqueurs"],"Stay organized":["Bien organisé"],"Black Friday email deals":["Offres Black Friday pour la messagerie électronique"],"Don’t just take our word for it":["Ce qu'en disent nos utilisateurs"],"Our story":["Notre histoire"],"Transfer your data from Google in one click":["Transférez vos données depuis Google en un clic"]},"specialoffer:tooltip":{"Access blocked content and browse privately. Includes ${ TOTAL_SERVERS }+ servers in ${ TOTAL_COUNTRIES }+ countries, connect up to 10 devices, access worldwide streaming services, malware and ad-blocker, and more.":["Accédez aux contenus bloqués et naviguez en toute confidentialité. Comprend plus de ${ TOTAL_SERVERS } serveurs répartis dans plus de ${ TOTAL_COUNTRIES } pays, la possibilité de connecter jusqu'à 10 appareils, l'accès aux services de streaming dans le monde entier, un bloqueur de logiciels malveillants et de publicités et d'autres fonctionnalités."],"Easily share your calendar with your family, friends or colleagues, and view external calendars.":["Partagez facilement votre calendrier avec votre famille, vos amis ou collègues et consultez des calendriers externes."],"Includes support for 1 custom email domain, 10 email addresses, 10 hide-my-email aliases, calendar sharing, and more.":["Comprend la prise en charge de 1 domaine de messagerie personnalisé, de 10 adresses e-mail, de 10 alias « hide-my-email », du partage de calendriers et bien d'autres fonctionnalités."],"Includes support for 3 custom email domains, 15 email addresses, unlimited hide-my-email aliases, calendar sharing, and more.":["Comprend la prise en charge de 3 domaines de messagerie personnalisés, de 15 adresses e-mail, d'un nombre illimité d'alias « hide-my-email », du partage de calendriers et bien d'autres fonctionnalités."],"Manage up to 25 calendars, mobile apps, secured with end-to-end encryption, 1-click calendar import from Google, and more.":["Jusqu'à 25 calendriers, des applications mobiles, la sécurité avec le chiffrement de bout en bout, l'importation de calendrier en un clic depuis Google..."]},"Status Banner":{"At the moment we are experiencing issues with the Proton VPN service":["Nous rencontrons actuellement des problèmes avec le service Proton VPN."],"Learn more":["En savoir plus"]},"Status banner":{"Learn more":["En savoir plus"],"Please note that at the moment we are experiencing issues with the ${ issues[0] } service.":["Nous rencontrons actuellement des problèmes avec le service ${ issues[0] }."],"We are experiencing issues with one or more services at the moment.":["Nous rencontrons actuellement des problèmes avec un ou plusieurs services."]},"suggestions":{"Suggestions":["Suggestions"]},"Support":{"Sub category":["Sous-catégorie","Sous-catégories"]},"Support article":{"${ readingTime } min":["${ readingTime } minute","${ readingTime } minutes"],"Category":["Catégorie","Catégories"],"Didn’t find what you were looking for?":["Vous ne trouvez pas ce que vous cherchez ?"],"General contact":["Contact - Général"],"Get help":["Obtenir de l'aide"],"Legal contact":["Contact - Juridique"],"Media contact":["Contact - Média"],"Partnerships contact":["Contact - Partenariats"],"Reading":["Lecture"]},"Support categories":{"Browse Proton product support":["Parcourez le support produit Proton"]},"Support category":{"There is no article in this category yet.":["Il n'y a pas encore d'article dans cette catégorie."]},"Support troubleshooting":{"--- Select ---":["--- Sélectionner ---"],"App version":["Version de l'application"],"Browser":["Navigateur"],"Check if this helps":["Vérifiez si cela vous aide."],"Choose a category for your question":["Choisissez une catégorie pour votre question"],"Choose a product":["Choisir un produit"],"Did this solve your issue ?":["Cela a-t-il résolu votre problème ?"],"Faster assistance is just a few clicks away — please make your selections":["Il suffit de quelques clics pour obtenir une assistance plus rapide, faites votre sélection."],"No, contact support":["Non, contacter le support"],"Proton account":["Compte Proton"],"Proton Bridge":["Proton Bridge"],"Proton Calendar":["Proton Calendar"],"Proton Drive":["Proton Drive"],"Proton for Business":["Proton for Business"],"Proton Mail":["Proton Mail"],"Proton Pass":["Proton Pass"],"Proton VPN":["Proton VPN"],"Thank you for your feedback":["Nous vous remercions pour votre commentaire."],"Troubleshooting":["Dépannage"],"What can we help with ?":["Comment pouvons-nous vous aider ?"],"Yes":["Oui"]},"support_modal_search_query":{"Search query":["Recherche"]},"support_search_button":{"Search":["Rechercher"]},"support_search_i_am_looking_for":{"I'm looking for":["Je recherche des informations sur..."]},"SupportForm":{"For a faster resolution, please report the issue from the Bridge app: Help > Report a problem.":["Pour que le problème soit résolu plus rapidement, vous pouvez le signaler à partir de l'application Bridge : Aide > Signaler un bug."],"Information":["Informations"]},"SupportForm:option":{"Account Security":["Sécurité du compte"],"Contacts":["Contacts"],"Custom email domain":["Domaine de messagerie personnalisé"],"Email delivery and Spam":["Distribution des messages et indésirables/spam"],"Encryption":["Chiffrement"],"Login and password":["Identifiant et mot de passe"],"Merge aliases and accounts":["Fusion des alias et des comptes"],"Migrate to Proton":["Migration vers Proton"],"Notifications":["Notifications"],"Other":["Autre"],"Plans and billing":["Abonnements et facturation"],"Proton for Business":["Proton for Business"],"Sign up":["Inscription"],"Storage":["Espace de stockage"],"Users, addresses, and identities":["Utilisateurs, adresses et identités"]},"SupportForm:optionIntro":{"Select a topic":["Choisissez un sujet"]},"swiss_baseed_feature":{"Swiss based":["Basé en Suisse"]},"Testimonial":{"Awards":["Récompenses"],"Customers":["Clients"],"Featured":["Ils en parlent"],"Go to testimonial source":["Accéder aux commentaires"],"Reviews":["Avis"],"Videos":["Vidéos"]},"Text":{"Find the plan that's right for you":["Trouvez l'abonnement adapté à vos besoins"],"If you need help, check out our ${ supportLink }.":["Si vous avez besoin d'aide, consultez notre ${ supportLink }."],"The page you’re looking for might have been removed, or it could be an\nold link.":["La page recherchée a peut-être été retirée ou le lien utilisé n'est plus valide."]},"Title":{"On this page":["Sur cette page"],"Related articles":["Articles similaires"],"Share ${ thisPage }":["Partagez ${ thisPage }"],"Thank you!":["Merci !"],"this page":["cette page"]},"Tooltip":{"More information":["Plus d'informations"]},"tooltip_calendar":{"Create up to 20 custom & shareable encrypted calendars. On top of that, add up to 5 calendars from friends, family, colleagues, and organizations.":["Créez jusqu'à 20 calendriers chiffrés personnalisés et partageables. Ajoutez jusqu'à 5 calendriers d'amis, de membres de votre famille, de collègues ou d'organisations."]},"tooltip_vpn":{"Access blocked content and browse privately. Includes ${ TOTAL_SERVERS }+ servers in ${ TOTAL_COUNTRIES }+ countries, highest VPN speed, ${ TOTAL_VPN_CONNECTIONS } VPN connections, worldwide streaming services, malware and ad-blocker, and more.":["Accédez aux contenus bloqués et naviguez en toute confidentialité. Comprend plus de ${ TOTAL_SERVERS } serveurs répartis dans plus de ${ TOTAL_COUNTRIES } pays, la vitesse VPN la plus élevée, ${ TOTAL_VPN_CONNECTIONS } connexions VPN, l'accès aux services de streaming dans le monde entier, un bloqueur de logiciels malveillants et de publicités et d'autres fonctionnalités."],"Access blocked content and browse privately. Includes ${ TOTAL_SERVERS }+ servers in ${ TOTAL_COUNTRIES }+ countries, highest VPN speed, 10 VPN connections, worldwide streaming services, malware and ad-blocker, and more.":["Accédez aux contenus bloqués et naviguez en toute confidentialité. Comprend plus de ${ TOTAL_SERVERS } serveurs répartis dans plus de ${ TOTAL_COUNTRIES } pays, la vitesse VPN la plus élevée, 10 connexions VPN, l'accès aux services de streaming dans le monde entier, un bloqueur de logiciels malveillants et de publicités et d'autres fonctionnalités."]},"version_history_label":{"Version history":["Historique des versions"]},"version_history_tooltip":{"Store up to ${ versionHistoryNumber } versions of each file for up to ${ years } years":["Conservez jusqu'à ${ versionHistoryNumber } versions de chaque fichier pendant ${ years } ans."]},"vpn_features_link":{"View VPN plans":["Voir les abonnements VPN"]},"vpn_features_useCase":{"Access blocked content and browse privately":["Accédez aux contenus bloqués et naviguez en toute confidentialité"]}}},"unleashApi":"https://account.proton.me/api"};
// We need to import data (the framework context) from the server
// This Astro feature with define:vars works well but creates an inline script
// So we can't directly import the initFramework helper, we have to store the context
window.frameworkContext = frameworkContext;
})();
SMTP (Simple Mail Transfer Protocol)(new window) is a standard internet protocol that mail servers use to send and receive emails. If a mail server can’t send an email, it replies with an SMTP error message.
SMTP error messages are messages mail servers send if an incoming or outgoing message bounces. They provide valuable information about why the message wasn’t delivered successfully.
Reviewing the SMTP error code in the bounce message can help you diagnose and resolve the issue.
What do SMTP error messages look like?
SMTP error messages are generally made up of three parts:
1. Reply code
2. Status code
3. Description
xyz Example: 550
x.y.z Example: 5.1.1
Example: “The email account that you tried to reach does not exist.”
Each digit (x, y, and z) in the reply and status codes indicates extra detail about the error.
Here’s an example of an SMTP error message:
SMTP reply codes refer to different aspects of the email service and can indicate issues such as:
The intended recipient’s email address is not registered with the service.
The message has been marked as spam or flagged for containing a virus.
The sender’s domain has been identified as a source of spam.
The email message violates the company’s email policy, such as containing sensitive information like credit card numbers or using prohibited language.
Not all SMTP reply codes indicate errors. Reply codes starting with a “4” or “5” are errors.
Types of SMTP error codes
Errors in SMTP are categorized into two main groups based on the starting digit of the reply code:
Error codes starting with a “4” indicate temporary failures: No immediate action is needed, and the sender’s mail server will automatically retry sending the email.
Error codes starting with a “5” indicate permanent failures: Action is required to resolve the issue and successfully deliver the email.
Understanding and responding to SMTP error codes can help quickly resolve email delivery problems.
For further assistance on email delivery issues, please send us the details of your error using our support form(new window).
Common SMTP 400 error codes
Error code
SMTP error message
Explanation
421
4.3.0 Temporary System Problem. Try again later.
Temporary issue on the server side; asking the sender to retry later.
421
4.4.5 Server busy, try again later.
The server is currently overloaded; requesting the sender to retry later.
421
4.7.0 IP not in whitelist for RCPT domain, closing connection.
The sending IP address isn’t authorized to send emails to the recipient domain.
421
4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address.
The sending IP address has been blocked temporarily due to suspected spamming.
421
4.7.0 Temporary System Problem. Try again later.
Temporary issue on the server side; asking the sender to retry later.
421
4.7.0 TLS required for RCPT domain, closing connection.
The recipient domain requires TLS encryption for email transmission.
421
4.7.0 Try again later, closing connection. This usually indicates a DoS for the SMTP relay at the HELO stage.
Denial of Service (DoS) attack on the SMTP relay during the initial handshake.
450
4.2.1 The user you are trying to contact is receiving mail too quickly. Please resend your message later.
The recipient’s mailbox is temporarily overloaded; asking the sender to try again later.
450
4.2.1 The user you are trying to contact is receiving mail at a rate that prevents additional messages.
The recipient is receiving emails too quickly, and further messages are delayed.
450
4.2.1 Peak SMTP relay limit exceeded for this customer. This is a temporary error.
The maximum number of SMTP relays has been reached, causing a temporary error.
451
4.3.0 Mail server temporarily rejected message.
Temporary rejection of the message by the recipient’s mail server.
451
4.3.0 Multiple destination domains per transaction are unsupported. Please try again.
Attempt to send emails to multiple domains in a single transaction, which isn’t supported.
451
4.4.2 Timeout – closing connection.
The server closed the connection due to a timeout.
451
4.5.0 SMTP protocol violation, visit RFC 2821.
The SMTP protocol was violated during the exchange of commands.
452
4.2.2 The email account that you tried to reach is over quota.
The recipient’s mailbox is full and cannot accept more messages.
452
4.5.3 Domain policy size per transaction exceeded, please try this recipient in a separate transaction.
The email policy size for the recipient domain has been exceeded.
452
4.5.3 Your message has too many recipients.
The message has too many recipients, and the server can’t process it in a single transaction.
454
4.5.0 SMTP protocol violation, no commands allowed to pipeline after STARTTLS, visit RFC 3207.
A violation of the SMTP protocol occurred after initiating TLS encryption.
454
4.7.0 Cannot authenticate due to temporary system problem. Try again later.
Temporary issue preventing authentication; asking the sender to retry later.
454
5.5.1 STARTTLS may not be repeated.
Attempting to restart TLS encryption when it’s not allowed.
Common SMTP 500 error codes
Error code
SMTP error message
Explanation
501
5.5.2 Cannot Decode response.
The server can’t decode the response from the client.
501
5.5.4 HELO/EHLO argument is invalid.
Invalid argument provided during the HELO/EHLO stage of SMTP.
502
5.5.1 Too many unrecognized commands, goodbye.
The server received too many unrecognized commands and terminates the connection.
502
5.5.1 Unimplemented command.
The server received an unimplemented command and terminates the connection.
502
5.5.1 Unrecognized command.
The server received an unrecognized command and terminates the connection.
503
5.5.1 EHLO/HELO first.
The client should send the EHLO/HELO command first before any other commands.
503
5.5.1 MAIL first.
The client should send the MAIL command before the RCPT command.
503
5.5.1 RCPT first.
The client should send the RCPT command after the MAIL command.
503
5.7.0 No identity changes permitted.
The server doesn’t allow changes to the message sender identity.
504
5.7.4 Unrecognized Authentication Type.
The server doesn’t recognize the authentication type used by the client.
530
5.5.1 Authentication Required.
Authentication is required to send emails through the server.
530
5.7.0 Must issue a STARTTLS command first.
The client must issue the STARTTLS command before attempting to authenticate.
535
5.5.4 Optional Argument not permitted for that AUTH mode.
An optional argument isn’t allowed for the specified authentication mode.
535
5.7.1 Application-specific password required.
An application-specific password is required for authentication.
535
5.7.1 Please log in with your web browser and then try again.
The user must log in through the web browser to resolve authentication issues.
535
5.7.1 Username and Password not accepted.
The provided username and password aren’t accepted for authentication.
550
5.1.1 The email account that you tried to reach does not exist.
The recipient’s email address doesn’t exist or is misspelled.
550
5.2.1 The email account that you tried to reach is disabled.
The recipient’s email account is disabled and can’t receive messages.
550
5.2.1 The user you are trying to contact is receiving mail at a rate that prevents additional messages.
The recipient is receiving emails too quickly, and further messages are delayed.
550
5.4.5 Daily sending quota exceeded.
The sender has exceeded their daily email sending quota.
550
5.4.5 Daily SMTP relay limit exceeded for user.
The sender has exceeded their daily SMTP relay limit.
550
5.7.0 Mail relay denied.
The server has denied mail relay for the sender’s IP address.
550
5.7.1 Email quota exceeded.
The recipient’s email account has exceeded its quota and can’t receive more messages.
550
5.7.1 Invalid credentials for relay.
The provided credentials for SMTP relay are invalid.
550
5.7.1 Our system has detected an unusual rate of unsolicited mail from your IP address.
The sender’s IP address has been blocked due to suspected spamming.
550
5.7.1 Our system has detected that this message is likely unsolicited mail.
The message has been blocked as it appears to be spam.
550
5.7.1 The IP you’re using to send mail is not authorized to send email directly to our servers.
The sender’s IP isn’t authorized to send emails directly to the recipient’s server.
550
5.7.1 The user or domain you are sending to (or from) has a policy that prohibited the mail that you sent.
The recipient domain has a policy that blocked the sent email.
550
5.7.1 Unauthenticated email is not accepted from this domain.
The server doesn’t accept unauthenticated emails from the specified domain.
550
5.7.1 Daily SMTP relay limit exceeded for customer.
The sender has exceeded their daily SMTP relay limit.
550
5.7.26 Unauthenticated email from domain-name is not accepted due to the domain’s DMARC policy.
The domain’s DMARC policy is blocking unauthenticated emails.
552
5.2.2 The email account that you tried to reach is over quota.
The recipient’s mailbox is full and can’t accept more messages.
552
5.2.3 Your message exceeded Google’s message size limits.
The message size exceeds the maximum allowed by Google’s email service.
553
5.1.2 We weren’t able to find the recipient domain.
The recipient domain doesn’t exist or has a typo in the email address.
554
5.6.0 Mail message is malformed. Not accepted.
The email message is malformed and can’t be accepted.
554
5.6.0 Message exceeded 50 hops, this may indicate a mail loop.
The message has passed through too many servers, suggesting a mail loop.
554
5.7.0 Too Many Unauthenticated commands.
The server received too many unauthenticated commands and terminates the connection.
555
5.5.2 Syntax error.
The server encountered a syntax error in the client’s command.