Solved E-Mail Notifications Failing for Gmail SMTP

[dkirk-ads]

Debian installation running v20, multi-year user of Google Workspace and Gmail for our email server. Last week Gmail began bouncing our notification emails stating "[35.xxx.xxx.xxx] Gmail has detected an unusual rate of 5.7.28 unsolicited mail originating from your IP address. To protect our 5.7.28 users from spam, mail sent from your IP address has been blocked". The stated IP address is correctly entered into the Google Gmail IP white-list and after just shy of two hours with supposed Google tech support they basically walked away telling me I need to turn on two-factor authentication for my 3CX account. They could not tell me why the white-list was failing suddenly, hours wasted there.

Anybody using Gmail successfully and if so, how?

When I try to use the 3CX SMTP server it replies "5.7.0 Denied", why is that?

This has worked for years through multiple 3CX versions, now it's a problem and voice-mails are not being heard as I finally got everyone convinced to accept them as emails. Thanks in advance for any guidance.

 

[NikolasA_3CX]

Hi @dkirk-ads

The error 5.7.0 Denied that you are seeing is commonly seen when the FQDN IP and the External IP of the PBX are not the same.
Please check if this is the case and ensure that they are the same and the issue will be fixed.

 

[dkirk-ads]

Hi @dkirk-ads

The error 5.7.0 Denied that you are seeing is commonly seen when the FQDN IP and the External IP of the PBX are not the same.
Please check if this is the case and ensure that they are the same and the issue will be fixed.

Aren't we supposed to have the DNS split like that, with internal IP and external IP with name in two different zones?

 

[NikolasA_3CX]

The Split DNS is for resolving the FQDN internally, but the FQDN IP and the External IP need to be the same.

 

[dkirk-ads]

<sigh> ... one digit off, my bad, amazing its worked so long without issue until recently! <embarrassed>

 

[NikolasA_3CX]

We are glad the issue is resolved