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3CX SMTP blacklist?

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layton

Bronze Partner
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Client has been running a 3CX Std license for several years using their own SMTP server. After recently upgrading them to v15.5, this obviously changed to using the 3CX SMTP server. During the upgrade, we missed that the client had a dummy extension setup to act as a general voicemail box, with voicemails being emailed to a custom distribution list. The email address for the distribution list was never intended to receive outside emails, so it was never added to the 3rd party hosted spam filter (since 3CX was connecting to the client's mail server directly, the internal DL address resolved just fine). Needless to say - the client stopped getting the general voicemail emails since the external spam filter was rejecting the message. It took the client a few weeks to realize this was happening, and then we were able to trace down the cause.

The issue at hand is that even though the mail setup has been resolved (and the DL can successfully receive emails from outside now), 3CX emails to the DL never arrive. 3CX emails for all other users are received as expected. Detailed logs in the hosted spam filter show the 3CX SMTP server isn't even attempting to send the message to the DL. If we change the email address on the dummy extension and leave a test VM, the email with that VM gets sent to the new email address successfully. If we revert it back to the original address, and try again - the message is never received.

I'm guessing the 3CX SMTP server detected the bounces to the DL address and blacklisted that email address - and it isn't even trying to send those now, which I get - 3CX obviously wants to manage that traffic and eliminate as much unnecessary noise as possible. My question is whether anyone else has dealt with this and how do we go about getting this address allowed again? I'd hate to burn a support ticket if I don't have to.
 
@layton

Haven't had that issue and I agree it would be silly to burn a paid support ticket for but it's definitely something that 3CX/support would need to resolve. I'd recommend reaching out to a partner to open a ticket on your behalf.
 
perhaps add an alias to the distribution group...
 
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Hello @layton

Please note that you will need to create a support ticket with our support department in order for them to track down the issue with the email address and help you resolve it. This is something only our support department can do.
 
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