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Inbound error codes

Understanding Email Transfer Error Responses

This page lists and tries to explain errors you may have received while attempting to deliver messages to Vade Managed Service. The SMTP response you received contains a unique code starting with OXSUS_. Find the code below to explain the issue you are experiencing and find remediation tips.

_101

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because your email provider is listed on the Vade Threat Network list. If you think this blocking is not justified you can fill out an abuse request

This list contains IP addresses which have been identified as sending spam. We use this list to protect our subscribers from receiving spam.

_102

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because your email provider is listed on the Validity Blocklist. Please go to Validity Unlisting Webpage to get unlisted.

This list contains IP addresses which have been identified as sending spam. We use this list to protect our subscribers from receiving spam.

_103

421 4.2.1 Connection deferred

Vade Managed Service platform protects its users. We could not accept your email at the moment because the server is experiencing issues delivering to backend servers. There are too many messages in queue at the moment. You may retry delivering the message at a later time.

_105

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. The delivery is rejected as there is no reverse dns in place. Sending system's dns should be re-configured and message may be resent.

_107

550 5.7.1 Sender Blocked

Vade Managed Service platform protects its users. We could not accept your email because your email provider is listed on the Abusix Blocklist. Please go to Abusix Look up Webpage to see status.

This list contains IP addresses who are not allowed to send directly to any SMTP server. We use this list to protect our subscribers from receiving spam.

_110

421 4.2.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the email provider has opened too many connections from a single IP address. The message may be retried using a different SMTP session.

_130

421 4.2.1 Connection refused

Vade Managed Service platform protects its users. We monitor the spam ratio from your mail delivery system over a given time period. This message informs you that your mail delivery system has exceeded the spam ratio over a given period of time, and that the message may be retried at a later time.

_133

421 4.2.1 Connection refused

Vade Managed Service platform protects its users. We monitor the number of invalid recipients over a given time period. This message informs you that your mail delivery system has reached the maximum number of bad recipients over a given period of time, and that the message may be retried at a later time.

_136

421 4.2.1 Connection refused

Vade Managed Service platform protects its users by monitoring and if needed, rate limiting all inbound email traffic. This message informs you that the IP address of the mail delivery system has reached its limit by sending too many messages, and that the message may be retried at a later time.

_139

421 4.2.1 Connection refused

Vade Managed Service platform protects its users by monitoring and if needed rate limiting all inbound email traffic. This message informs you that the IP address of the mail delivery system has reached its limit by opening too many connections, and that the message may be retried at a later time.

_142

421 4.2.1 Connection refused

Vade Managed Service platform protects its users by checking the number of recipients your mail delivery system sent messages to over a given time period. This message informs you that your mail delivery system has reached the maximum number of recipients over a given period of time, and that the message may be retried at a later time.

_201

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because your email provider is listed on the Vade Threat Network list. If you think this blocking is not justified you can fill up a abuse request

This list contains IP addresses which have been identified as sending spam. We use this list to protect our subscribers from receiving spam.

_202

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because your Helo is not resolvable. For more information on troubleshooting this, please refer to rfc5321.

_203

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because it failed to pass SPF verification for the sending domain. For more information on troubleshooting this, please refer to rfc7208.

_204

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because your Helo is not resolvable. For more information on troubleshooting this, please refer to rfc5321.

_301

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the format of the sender address provided as part of the MAIL FROM command is invalid. Double check the sender address and try again later.

_303

421 4.2.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the sender domain is invalid or could not be verified. In other words we were not able to resolve that domain to an A or MX DNS record. The sender domain dns record needs to be corrected and sending may be retried later.

_304

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the domain used in the From: header either does not match the MAIL FROM address or the SPF record. Double check the domain in from header or correct SPF entry and try sending again later.

_305

421 4.2.1 Connection deferred

Vade Managed Service platform protects its users by rate limiting the number of transactions allowed in a single SMTP session. The current limit is set to 50 transactions per session. You may retry to deliver the message by disconnecting and using a new session.

_306

550 5.7.1 Connection refused

Vade Managed Service platform protects its users by using blacklisting based on behaviour. The mail from or mail from domain is blacklisted in the platform. We use this list to protect our subscribers from receiving spam.

_402

550 5.7.1 Recipient rejected

Vade Managed Service platform protects its users. We could not accept your email because the message was sent to a non-existent customer/user. These errors should be treated as an "unsubscribe" by the sender, if a bulk mailer.

_403

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the message was sent to a non-existent customer/user. These errors should be treated as an "unsubscribe" by the sender, if a bulk mailer.

_404

421 4.2.1 Connection refused

Vade Managed Service platform protects its users by enforcing tresholds on the number of recipients per message allowed in a single SMTP session over a given period of time. You may retry to deliver the message at a later time in a new session.

_405

421 4.2.1 Connection refused

Vade Managed Service platform protects its users by enforcing tresholds on number of recipients allowed for a single message. Your message has exceeded the treshold for number of recipients per message. Reduce number of recipients per message and retry sending later.

_406

550 5.7.1 Connection refused

Vade Managed Service platform protects its users. We could not accept your email because the format of the recipient's address provided as part of an RCPT TO command is invalid. Double check the format of the recipient address and retry sending later.

_507

550 5.7.1 Message rejected

Vade Managed Service platform protects its users. We could not accept your email because it failed to pass DKIM authentication for the sending domain. For more information on troubleshooting this, please refer to rfc5585. Verfiy DKIM settings and try sending again later.

_508

421 4.2.1 Connection deferred

Vade Managed Service platform protects its users. We could not accept your email because it failed to pass DKIM authentication for the sending domain. For more information on troubleshooting this, please refer to rfc5585. Verfiy DKIM settings and try sending again later.

_510

552 5.3.4 Message size limit exceeded

Vade Managed Service platform protects its users. We could not deliver your email because it exceeds the maximum size allowed on our servers, which is currently set to 28MB (29360128 bytes). Reduce message size and try sending again later.

_512

550 5.7.1 Message rejected

Vade Managed Service platform protects its users. Your message has been rejected due to from domain not being resolvable.

Double check the from address domain and retry sending later.

_513

550 5.7.1 Message rejected

Vade Managed Service platform protects its users. Your message has been rejected due to a sender blacklist configured by the recipient.

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