Starting backup failed - unable to start debug log

I’m running UrBackup server on FreeNAS with a total of 3 Windows 10 clients. All clients stopped backing up recently and I’ve been trying to troubleshoot. Clients are visible and showing online in UI, but when trying to launch a backup from the UI, I see “Starting backup failed”.

I tried to start the debug log at as described here, but the start up errors out with:

ERROR: LMDB: Failed to open LMDB database file (File exists)
ERROR: LMDB error creating env
ERROR: Could not create or open file entry index. Exiting