Error sending emails after update to v5.1.1

[demelos]

Your software
My Mautic version is: v5.1.1
My PHP version is: 8.0.30
My Database type and version is: 10.5.22-MariaDB

Your problem
My problem is: Email are not going out, I believe due to some weird error after I update to the latest version. even when trying to manually send an email I get an error (see image)

These errors are showing in the log:

Steps I have tried to fix the problem:

[adiux]

Are there no errors in the logs? Without an error it is very hard to say what might be the problem.

And, what mail server are you using to send your emails?

[joeyk]

Hi, did you update from 5.1 to 5.1.1 or from 4?