Comment 2 for bug 1890903

To debug the systemd-resolved service, you can run

$ sudo systemctl edit systemd-resolved

and in the editor that is opened, add and save this content:

[Service]
Environment=SYSTEMD_LOG_LEVEL=debug

then restart systemd-resolved, or reboot. Then once the problem happens again, check:

$ journalctl -b -u systemd-resolved

to see if there are any problems logged. You can check the current log also, as it may have logged some problems even without debugging enabled, although to check the logs for previous boots you should leave the -b parameter off.

If any problem was logged you can paste that part of the log here, or just attach the full log.