I'm having an issue with a sender using a Comcast.net email address who is trying to email our users. They're receiving the error message: "550 5.7.26 Unauthenticated email from comcast.net is not accepted due to domain's DMARC policy...". Our DMARC settings are currently set to quarantine, not reject, and we typically receive emails from Comcast without any problems. I consulted Google support, and they mentioned that the problem needs to be fixed on Comcast's side. I'm puzzled as to why this is only affecting one user. Any insights would be appreciated!
4 Answers
This issue often crops up due to an SPF or DKIM misconfiguration. If the sender's email isn't correctly authenticated, it can lead to these types of rejections. Encourage them to double-check their email routing to avoid compliance failures.
Just to clarify, your email system is working correctly by denying emails that don't meet the DMARC requirements. This rejection is because Comcast is enforcing its policy, not your own settings. You'll need to advise the user to contact Comcast for assistance.
It sounds like the sender might be using an unauthorized email server. DMARC policies are strict about authentication, and if they're sending from a server that Comcast doesn't recognize, that's likely why they're getting rejected. Even though they have a Comcast email address, it doesn't guarantee that all their emails are compliant with DMARC. You might want to suggest they check their email setup.
Good point! I’ll pass that on to them to see if they can sort out their sending server.
It seems like the rejection is on Comcast’s side, where their systems are denying the authentication of the user’s email. Changing the sending server or checking their email setup could resolve the issue. If they're using a third-party service to send emails, that could be the problem too.
Thanks for confirming that! I’ll recommend they reach out to Comcast about their email setup.