email not working

[jpeppas]

Hi to all.

I am running 20.0.7.1080 self-hosted. I have run in to an issue where emails are not being sent.

The error is:
The remote certificate was rejected by the provided RemoteCertificateValidationCallback.

I have checked

• the mailbox credentials (ok)
• the mail server certificate (ok)
• mail server blacklist status (ok)

any idea why I am having this error?

 

[Evolute IT]

What SMTP config are you using?

 

[jpeppas]

I am using a custom SMTP server that I am an owner of. This is used in various applications, so I am sure it's working ok.

 

[KyriacosS_3CX]

What certificate is your mail server using for Secure SMTP? If it is self signed, or for a different host name, or you are using the IP in the 3CX SMTP config, or from an authority that does not have proper chaining to the well known certificate authorities, then the certificate it presents would no be possible to validate.

If you do not need it - especially if you trust the network between the PBX and the mail server, then you can disable SSL/TLS.

 

[jpeppas]

The certificate is a 3rd party official CA. The ssl checker is showing it's ok. This was working, since I had previously received emails from the PBX. Somewhere between updates it seems to have broken

 

[KyriacosS_3CX]

Please log onto the PBX server itself via SSH and check if the time is set correctly.

 

[jpeppas]

 

[KyriacosS_3CX]

can you run timedatectl status and share the output? From first glance it looks OK, but best be sure.

 

[jpeppas]

 

[KyriacosS_3CX]

OK, this would confirm it's not a timing issue. Perhaps with logs in verbose mode we can get some more info of what the root cause of the problem is.
Are there any firewalls/AVs or similar in-between the PBX and mail server that may be interfering with certificates?

 

[jpeppas]

we have a transparent proxy, but this was in place before the issue arose. I will run some command to do a sanity check and post them here

 

[KyriacosS_3CX]

Please check and see if you can capture some verbose logs for this, so we can drill a bit further if possible - just remember to anonymise anything sensitive before sharing, verbose is, well, verbose.

 

[jpeppas]

OK. I fixed it.. I saw for some reason the certificate the mail server was reporting was the expired one, even though I have renewed it.. I deleted it, restarted the services, and now it works ok. thanks for the support.

Merry XMas to all

 

[KyriacosS_3CX]

Merry Xmas, glad you got it sorted before the 25th!