An error occurred! SMTP-error (-1): Connecting to the server failed (Ubuntu 22.)

[Civilpolisen]

Ubuntu 22.04, Roundcube 1.1.6

We needed to upgrade the server and when doing so, services stoped working!

Sending mail from Roundcube was one of them! Users can't send mail and I'm out of ideas to try...!

"An error occurred! SMTP-error (-1): Connecting to the server failed."

I have checked the logs, I have changed ports... I have NOT restarted the service since I can't find a service to restart!
Last option is of-course, to simply "sudo reboot" the server itself... That will do it! :-)

Pages suggests certificates are outdated... but how to solve remains a mystery!

Any ideas of a path forward in this issue!?

[JohnDoh]

There is no Roundcube "service" because Roundcube is a web application. The error means Roundcube cannot connect to your SMTP server. So start from there, can you connect to it via telnet for example?