how to use logging on weconnect-mqtt?

[Domoberry]

Newbie question probably...
Every now and then weconnect-mqtt (0.49.2 on RPI4) stops working, "sudo systemctl status weconnect-mqtt" reports "inactive (dead)". Using "sudo systemctl restart weconnect-mqtt" gets things back to normal (note: logout/in from the app or website does not help in this case obviously).
To better understand what happens, I would like to enable logging for weconnect-mqtt. In the systemctl start-up script, the option "--verbose" is added.
Where should I look for the log files?