Got the same problem. I shut down omv to make a copy if the systemdrive.
After reboot it stopped working. I found out that the raspberry was defect. So bought a new one and wrote the backup back to the ssd.
After startup eth0 was missing.
I just turned it on manually with
After that I was able to login via the gui. I set a static ip there and rebooted the system. After that it worked.