Radarr - Lost Web UI - ERR_CONNECTION_REFUSED

Just can’t figure this one out on my one…

Last weekend i updated my Linux machine (Ubuntu 16.04) where i have both Sonarr an Radarr running for almost 6 months with no issue.

The update took some time but it finished without errors at least that i’ve seen. Since then i lost my web UI and it doesnt show up even with the “incognito” metod. My Web UI in Sonarr is fine.

When i run the sudo systemctl status radarr command it says it’s active (running)

What can i do to try and get my user interface back? Any suggestions?
Many thanks in Advanced

Kátia