Acymailing is giving me the following error for newsletter recipients using only one specific domain.
Error sending message APCAA Newsletter 2020-07-28 test 2 to xxxx@amicentral.org , , , (xxxx@amicentral.org: User does not exist ) SMTP server error: Called RSET without being connected
(the actual email address has been redacted in this post)
From a previous post here, and some investigative work with the admins at the domain in question, we have deducted Acymailing is refusing to send emails to users with this domain because this server is responding to queries that it is set as a catchall server, and therefore it will not verify that ANY email address is valid and just accepts all.
I have determined from their admins that this company is using a microsoft exchange mail server in it's default configuration. The admins of the server have indicated to me that Microsoft techs informed them that this status message is default for microsoft exchange mailservers and there's no way to alter it.
So, if this is true, then that means that Acymailing should be refusing to send mail to any domain using a microsoft exchange mailserver, which I find unlikely.
Since I can't force the admins of this server to change their server's catchall status, is there a security switch in Acymailing that I can turn off to keep it from refusing to send to catchall servers?
I have disabled the Advanced email verification which checks if the domain exists in the Security tab of the Acymailing component but the error persists.
We are using AcyMailing Enterprise 6.13.3
As previously noted, Acymailing was delivering to this domain previously, and began to through this error some time in May, 2020. I can't find where that coincides with any changes we made on our end, or that the company made on their end.
Any thoughts or enlightenment we might get on how to get acymailing to ignore the catchall server response and send emails anyway would be much appreciated.