I have the same issue after ‘upgrading’ from a Raspberry Pi 3 to an Odroid XU4. I had it working from a fresh install about 8 days ago, and was configuring Sonarr and Radarr remotely using Remot3.it. I then noticed that I was unable to write to my NAS (Apple TimeCapsule) when attempting a bulk import, then while trying to troubleshoot that, this problem began. The dietpi installation on RPi using the same fstab entry has worked flawlessly, so it looks like I’ll have to use the RPi for Sonarr and Radarr until this is fixed. I’ve since re-imaged the eMMC from the default IMG, but have the same Sonarr and Radarr issue.
There is a related post which refers to issues posted on Github, but it seems this is still not fixed.
https://dietpi.com/forum/t/bug-sonarr-and-radarr-not-starting/2031/1