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Google Workspace Rejecting Sophos Setup Messages (and other important messages

Messages are being rejected by GMail with DMARC failures. Most of the messages are from well known senders such as Google, Microsoft, and the USDA. The senders' DKIM is in order and we have correct DMARC, SPF and DKIM settings with respect to our DNS. Gateways are in place per the documentation. GMail extra spam checks are turned off. Here's a rejection of the Sophos Central welcome email:

Received from an SMTP server with IP address: (TLS enabled)
550-5.7.26 Unauthenticated email from <a href="">" target="_blank"></a> is not accepted due to 550-5.7.26 domain&#39;s DMARC policy. Please contact the administrator of 550-5.7.26 <a href="">" target="_blank"></a> domain if this was a legitimate mail. Please 550-5.7.26 visit 550-5.7.26 <a href="">" target="_blank">> to learn about the 550 5.7.26 DMARC initiative.
Mar 24, 2022, 4:32:23 PM
Has anyone else encountered this?
Google suppport said that it's an SPF issue, but I've triple-checked my settings and they're correct.

Edited tags
[edited by: Raphael Alganes at 6:02 AM (GMT -7) on 7 Jun 2023]
Parents Reply Children
  • I have double and triple-checked this and the only solution is to add each sender with a DKIM of "-all" who is rejected to the Gateways list. Google's support seems to not be able to see an issue with this, describing the behavior as normal. My solution, for now, is to disable Smart Banners for this tenant and rely on changing the Subject line.

  • Please ask google support to check your Gateway IP list in google workspace The email that fails DMARC does if come from one of those IP's? If so according to their documentation referenced above they should not be doing DMARC. I cannot see how this can be normal behavior if their document says it should not be doing this. It say inbound gateway should do DMARC checks, which is Sophos Central Email.