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RPGoldenberg's profile

2 Messages

Thursday, November 16th, 2023 12:33 AM

why are my e-mails sent to gmail accounts bouncing back as undeliverable? Help with DKIM and SPM

Recently my e-mails sent to anyone with a gmail account are undeliverable.  

 The message I get is that I need to authenticate with DKIM and/or SPF.  I don't know how to do this and ATT support said they did not have access to the servers to do this.  Any suggestions?  Below is the message:

Sorry, we were unable to deliver your message to the following address.

<[email scrubbed]>:
550: 5.7.26 This mail has been blocked because the sender is unauthenticated.
5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
5.7.26  Authentication results:
5.7.26  DKIM = did not pass
5.7.26  SPF [] with ip: [] = did not pass
5.7.26  To mitigate this issue, please visit Gmail's authentication guide
5.7.26 for instructions on setting up authentication:
5.7.26 v16-20020a05622a131000b00417d78906c7si9910541qtk.292 - gsmtp

Community Support


229.7K Messages

3 months ago

Hi @RPGoldenberg,


Thank you for reaching out on the AT&T Community Forums! We understand, and want to help with figuring out why aren't you been able to send those emails.


Emails may bounce back in Gmail due to reasons such as invalid recipient addresses, triggering spam filters, exceeding sending limits, or technical issues. It's important to identify the specific cause and take appropriate actions to improve deliverability.


Upon further review, our AT&T Postmaster Staff will be the ones best suited to assist with your email.


When their support team receives a request with the needed information, requests are evaluated. If granted, the block will be removed within 24 to 48 hours. There are situations when mail interruptions or blocks are in place outside the AT&T domain. In these cases, we will attempt to make contact with the party initiating the block and seek a resolution. If there is no change after 48 hours, please include the current and complete error message that you are receiving in your follow-up email to


Please feel free to reach back out if you need help in the future.


Happy to assist!


Jennifer, AT&T Community Specialist. 

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