Job finishes with "Error"

We have a Backup Job running on on of our Windows Servers, it works if the target directory is local but not when using sFTP. The useraccount can access the sFTP Storage fine.
The Log is only showing “Error” at the end without any other information.

Open two tabs to the Duplicati Web UI. On the first tab go to About → Show Log → Live → and set the dropdown to Warning. On the second tab trigger a backup operation, then go back to the first tab. You should be able to see the warnings/errors there.