SMTP Denied after IP Change Running V20

[dkirk-ads]

I'm running V20 on Debian and had to change the static public IP address, which went smooth, the firewall tests fine and no phone issues. The only issue remaining is the "5.7.0 Denied" whenever an e-mail is sent using the 3CX SMTP server. This used to work before the IP number change. I've poured through the settings and parameters and cannot find any method to cure this, does anybody have any ideas?

The FQDN matches the IP address, so that's not the problem. Nothing in the IP block list. Almost as if it might be something on the 3CX SMTP server side, maybe a cached DNS name/ip that didn't catch the change?

Our email is hosted by Google gmail and that is not an option in the Email settings. Setting up a "Custom" may be the only solution now.

 

[dkirk-ads]

Was able to send to Google's relay server at aspmx.l.google.com after locking the relay down to my ip address, turning off authentication and SSL/TLS. With/without credentials and with/without SSL/TLS wouldn't work using the smtp-relay.gmail.com and all three port numbers. Unfortunately the emails come in as spam even when I have the IP address flagged white in Gmail, yet another problem to solve now. Wish it would just work using the 3CX SMTP server.

 

[dkirk-ads]

Looks like Google is failing too

The following error occurred when trying to send an email with subject ‘New Voicemail from +1xxxxxxxxxx3 - TIA :HR Group’ to ‘[email protected]’ : 5.7.1 [xx.xxx.xxx.xxx] Messages missing a valid address in From: header, or 5.7.1 having no From: header, are not accepted. For more information, go to 5.7.1 https://support.google.com/mail/?p=RfcMessageNonCompliant and review 5.7.1 RFC 5322 specifications. r17-20020a05620a299100b007831b225795si193429qkp.187 - gsmtp

The 3CX email "Test" function works fine but in production this error above is what I'm seeing.