Office 365 / WiscMail / WiscMail Plus - Understanding SMTP errors

This information in this document is intended for email administrators or campus mass emailers who are seeing errors when sending email via smtpauth.wiscmail.wisc.edu. If you are a non-Office 365 user and are experiencing these errors, then please contact your email administrator. If you are a Office 365 user and are seeing these errors in your email client please contact the DoIT Help Desk for assistance.

5.7.1 ... You are not allowed to send email as from ...

An error occurred while sending mail. The mail server responded: 5.7.1 You are authenticated as yournetid@wisc.edu. You are not allowed to send email as from attempted_from_address. See KB doc https://kb.wisc.edu/3998 Or call the DoIT Help Desk for assistance. Please verify that your email address is correct in your Mail preferences and try again.

smtpauth.wiscmail.wisc.edu validates the from address that your client is configured to send as from. The server will allow you to send as:

  • Your primary address and any of your alternate addresses
  • Any address of any account to which you have linked access
  • Any other address (an address on an external system, WiscList, etc) that you have verified via the Send As Addresses option in the Wisc Account Administration site. Instructions to do this can be found here.

It is common for remote mail servers to reject, or mark your messages as spam, if you are sending as an external address (e.g. @gmail.com) if you're not using the authorized SMTP server for that domain. It is strongly recommended that you set up an additional SMTP profile in your client settings so that you may send mail through that provider's SMTP server.

452 Too many recipients specified.

The WiscMail servers will allow an authenticated sender using WiscMail's SMTP Auth service to specify 1000 recipients (To, Cc and Bcc combined) per message. The behavior is that the message will be submitted to the initial 1000 recipients, but excess recipients given are rejected with a 452 too many recipients specified error.

The WiscMail servers allow 128 recipients for incoming email messages from non-authenticated senders. The sending server/application should be able to recover from this error by complying with proper standards.

DoIT provides many options for sending mass email. Please visit Email Lists for more information.

550 5.1.1 unknown or illegal alias

This error message means that the email address does not exist on the server.

If this error message comes back to you in an email "Delivery Notice" message, it means that your client was able to send the message to your outgoing server, however your outgoing server was not able to deliver the message to the server that hosts the account. Most outgoing servers (including smtpauth.wiscmail.wisc.edu) will deliver the message to the remaining recipients, so you only need to re-send the message to the failed recipient once you have corrected their email address. However, this depends on your outgoing mail server, so it is recommended that you verify this behavior.

If this error message was given to you by your client, it means that your outgoing server was unable to accept the message because of the invalid recipient address. Most clients (including the WiscMail Web Client) will abort the entire message and not deliver the message to the remaining recipients, so you should correct the email address of the failed recipient and then re-send the message to all recipients. However, this depends on your client, so it is recommended that you verify this behavior.

553 5.1.8 - Domain of sender address does not exist.

This error message means that sender's from email address does not exist on the server.

452 4.2.2 user over quota; cannot receive new mail

This error message means that the account to which the email was addressed is over-quota and the email cannot be delivered.

If this error message was given to you by your client, it means that your outgoing server was unable to accept the message because of the over-quota recipient. Most clients (including the WiscMail Web Client) will abort the entire message and not deliver the message to the remaining recipients, so you should temporarily exclude the email address of the failed recipient and then re-send the message to all other recipients. You can then re-send the message to the failed recipient once they are under quota and capable of receiving the message. This may depend on your client, so it is recommended that you verify this behavior.

If this error message comes back to you in an email "Delivery Notice" message, it means that your client was able to send the message to your outgoing server, however your outgoing server was not able to deliver the message to the server that hosts the account. Most outgoing servers will deliver the message to the remaining recipients, so you only need to re-send the message to the failed recipient once they are under quota and capable of receiving the message. However, this depends on your outgoing mail server, so it is recommended that you verify this behavior.

4.2.1 Mailbox Temporarily Disabled.

This error indicates that the recipient's email address was valid but the account has been deactivated. There is no forward set on the account.

450 4.5.3 No more transactions allowed.

The WiscMail servers will allow a sender to perform multiple smtp transactions (messages) once connected. However, to prevent abuse, the servers will only allow 50 transactions before returning a 452 temporary error. The sending server should respond to 452 temporary errors by reconnecting to send the rest of the messages.

Please note that a single smtp transaction can include multiple recipients. This will not affect messages that have more than 50 recipients. There is no limit to the maximum number of recipients allowed per message.

If you are a mass mailer that is experiencing this error in your logs, it can be ignored. If your messages are being rejected because of this error, then there is a problem with your mailer's ability to retry the messages or respond to 4xx temporary error codes.

Since the method for recovering from this error involves reconnecting to send additional messages, it is common for mass mailers to also experience 421 - connection refused - errors. The combination of these two restrictions may make it difficult for some mass mailers to send large numbers of messages. If your mailer software is having problems, it is recommended that you utilize an RFC compliant mail transfer agent that is capable of queuing messages (e.g. sendmail). Alternatively, you can utilize DoIT's mass mailing service.

Your account has been sending a lot of messages that appear to be spam.

There have been a number of compromised WiscMail accounts due to users giving their passwords away to phishers. The WiscMail team has started implementing moderate outbound spam rate limiting to prevent the spammers from using the WiscMail servers to deliver millions of messages out to the rest of the world.

The WiscMail team has implemented a restriction that rate-limits outbound mail detected as spam to about 50 messages per hour per user. Anything above that will be rejected back to you so that you can retry at a later time. The WiscMail team recognizes that outbound spam scanning is not 100% accurate and there is also a legitimate need for WiscMail users to send mass mail out through the WiscMail servers. That is why the WiscMail servers do not rate-limit all of your messages that are detected as spam, and they do not rate-limit any messages that are not detected as spam. The WiscMail team believes that this hybrid approach is the best way to stop excessive abuse with minimal impact on WiscMail users.

The most common cause for your messages to be rated as spam is due to your computer's internet address being listed as having a reputation for sending spam. It's common for your internet service provider to assign your computer an address that was previously used by an infected computer that was sending spam. If you're only sending a few intermittent messages you shouldn't have a problem since WiscMail will allow around 50 spam messages per hour.

Excessive email sent external this hour

There have been a number of compromised WiscMail accounts due to users giving their passwords away to phishers. The WiscMail team has started implementing moderate outbound rate limiting to prevent the spammers from using the WiscMail servers to deliver millions of messages out to the rest of the world

  • Excessive email sent external this hour - Please contact support for better mass email alternatives – 1,000 limit per hour

Excessive email sent today.

There have been a number of compromised WiscMail accounts due to users giving their passwords away to phishers. The WiscMail team has started implementing moderate limiting to protect the campus from large spam outbreaks without limiting the campus business.

  • Excessive email sent this hour - Please contact support for better mass email alternatives – 40,000 limit per hour
  • Excessive email sent today - Please contact support for better mass email alternatives – 50,000 limit per day

Unable to send email

If you receive the following errors/bounce back messages:

  • "The delivery has failed to these recipients or groups: your message couldn't be delivered, your email address is suspected of sending spam and can't send outside of your organization. Please contact your email admin."
  • "The message couldn't be delivered because you weren't recognized as a valid sender. The most common reasons for this is that your email address is expected of sending spam and its no longer able to send messages outside of your organization. Contact your email admin for assistance."

Your account may be blocked by Microsoft. Please contact the DoIT Help Desk to further troubleshoot this error.

Other Errors

  • 450 4.1.8 invalid/host-not-in-DNS return address not allowed (Usually inbound)
  • 451 4.4.3 Please try again later
  • 550 5.1.8 invalid/host-not-in-DNS return address not allowed (Usually outbound)
  • 550 5.2.4 alias failed to expand to any valid addresses
  • 550 5.7.1 WiscMail error 1279. Invalid from address
  • 550 5.7.1 Bad reputation
  • 552 5.2.3 Message exceeds local size limit
  • 554 5.1.4 Mail hop exceeded possible mail loop

4xx errors vs. 5xx errors

Messages should not be rejected as a result of 4xx error codes. 4xx error codes are temporary errors that are designed to tell the sender to try sending at a later time. The only time that a server should reject a message as a result of 4xx error codes from WiscMail servers is if the sending server decides to stop retrying the messages. In this case, the sending server should reject the message with its own 5xx error code (e.g. 554 Transaction failed).




Keywords:4.5.3 No more transactions allowed too many connections please reduce connections per minute 4xx 452 450 400 5xx 500 550 553 5.1.1 5.1.8 smtp send wiscmail throttle throttling mass mailings spam reject error smtp unknown illegal alias can't send netid email 4.2.1 Mailbox Temporarily Disabled size of message Unknown or Illegal Alias exceeds temporary size limit recipients office 365 o365   Doc ID:3998
Owner:Ara M.Group:Office 365
Created:2005-09-07 19:00 CDTUpdated:2016-09-08 10:52 CDT
Sites:DoIT Help Desk, DoIT Tech Store, Office 365, WiscMail
Feedback:  26   37