3CX SMTP server error SSL TLS

[nsa-th]

Hi

I recently installed the free standard edition, and the email has been set to use 3CX SMTP server. It was working fine for a while, and suddenly I'm not getting email out.

When testing the mail server, I'm getting this error:

An error occurred while attempting to establish an SSL or TLS connection. The SSL certificate presented by the server is not trusted by the system for one or more of the following reasons: 1. The server is using a self-signed certificate which cannot be verified. 2. The local system is missing a Root or Intermediate certificate needed to verify the server's certificate. 3. The certificate presented by the server is expired or invalid. See https://github.com/jstedfast/MailKit/blob/master/FAQ.md#InvalidSslCertificate for possible solutions.

Is that a known issue? anyway to troubleshoot or fix that?

 

[pkostovasilis]

I think this happened to a customer recently when they changed their external IP address.
Because he was having issues with the remote extensions due to this change we had to re-install the instance anyhow. After the installation smtp worked. I think the smtp account is bound to the external IP that is set during installation. (if someone from 3cx knows otherwise, let me know so i can delete this false info)

If that's not the case (the external ip on your dashboard matches your current ip address) please try the following thread and maybe one of the solutions fits you
https://www.3cx.com/community/threads/smtp-services-not-working.56421/

 

[nsa-th]

Actually it's now working again. I'm not really sure why, but it might be related to time also. Previously the NTP traffic was blocked, it's one of the things I tried to resolve the issue.

 

[YiannisH_3CX]

After the installation smtp worked. I think the smtp account is bound to the external IP that is set during installation. (if someone from 3cx knows otherwise, let me know so i can delete this false info)

The 3CX SMTP is bound to the public IP of the PBX but not in the way you think. The SMTP will validate against the activation server and will try to match the IP the PBX activated from with the IP of the request from the SMTP. If those do not match then you will get an error "Invalid Credentials".
You can however solve this by setting the PBX to Dynamic Public IP and restarting the 3CX services. This will force the PBX to detect the new IP and update the activation server. Once that is done the issue will be resolved. There is no need to re-install the phone system.

 

[YiannisH_3CX]

Actually it's now working again. I'm not really sure why, but it might be related to time also. Previously the NTP traffic was blocked, it's one of the things I tried to resolve the issue.

Glad to see the issue has been resolved.