I used this guide,
Tried this twice, with completely fresh reinstalls of OMV, but get the same issue. 192.168.1.20:7878 is not reachable. All the other port numbers are, however. I'm able to pull up Lidarr, Sonarr, Jackett, Lazy Librarian without issue. But I can't open the radarr associated web UI.
Running this on a Raspberrypi 4 with an external hard drive.