Martin, this behavior might indicate that GMail believes the domain is hosted on their side. Was this domain name ever on a GSuite account by chance? If not, I'd be on the lookout for an improperly configured outgoing gateway. Hope that helps!

Hello Kyle

The GMail address is my private E-Mail address at gmail.com. Not only GMail is affected: We tried to send an EMail to unlocktheinbox.com to check if DMARC and DKIM are allright. We got the same error message.

As i wrote, the behaviour started at the time, after i upgraded the Mail-Server a while ago.

I also compared the settings of the affected domain with others, no difference at all. It's really odd.

Since the DNS is not under our control, i asked for details. Maybe they have a problem there.

Thanks!

Dear Kids, don't do that at home:

The account had a SMTP account under "Connectivity" with the same credentials and data of its own EMail-Account! This might confuse everything and everybody. After deleting this SMTP account, everything is fine.

I can only guess: Older versions of SmarterMail where able to deal with this silly situation and newer don't.

Maybe SmarterMail might program a checking functionality, which disallows to enter an existing EMail-Account of the SmarterMail-Server as an external SMTP-Account.

Cheers!

Hi Martin, glad you got that figured out! 

I'm sorry to hear the web interface did not prevent this from being accomplished. I did a quick test in our latest release as well and here too it allowed me to create an SMTP Account with the same credentials as my main account. 

I don't think that is expected behavior, so I'm going to document this with our development team so we can get it resolved in the near future. Thanks again Martin, I appreciate you following up with your findings. 

Coming up in the next BETA release, the interface will now check if you are trying to test or save an SMTP account with information that links back to the same account on the server, and throw an error if it detects it. Thank you for reporting this issue. Please let me know whether or not it works out for you.