It looks like uploading and maybe downloading worked, but listing didn’t. You could try different slashes.
Repair freezes (or takes days) noted that it needs forward slashes. Also try with/without leading/trailing.
I’m assuming you have something in GUI “Path on server”, but you can probably play in tester URL too.
Duplicati internally expects URLs to have forward slashes, and WebDAV (HTTP based) likely does too.
Exactly what the slash policy should be at the start and end of the path in the GUI is harder to guess at.
" * SQL logic error no such table: LogData is the sort of thing you might see if you don’t have a backup already made, yet ask for logs (maybe the FetchLogData that’s posted). As a general Duplicati caveat, whenever a backup errors, if there are no longs for the backup, try server log at About → Show log too.