Need more log info

Nextlcoud 17.0.5 Centos 7.5

I’m getting this error suddenly. What I can’t find is where the logs are at when you send a test email and get an error.
A problem occurred while sending the email. Please revise your settings. (Error: Expected response code 220 but got code "554", with message " (mreueus004) Nemesis ESMTP Service not available 554-No SMTP service 554 IP address is black listed. ")

The IP of the server isn’t on any black lists but neither is the provider which is ionos.

Where can i find a log where this information might be?

Right now 1st tier tech support with 1and1 and saying it’s not 1and1. So I’m asking where can i find where this function might log to? It’s not in the GUI under logging, not that I can see.

You can change the log level to be more verbose so that more message are written to the Nextcloud log file, which you should find in the Nextcloud data directory by default. The Nextcloud administrator guide should describe the available parameters in more detail.