Backup stucks at "Indexing"



I’m new to Urbackup and try to backup my remote Debian 7 (Wheezy) server to my local Notebook running Windows 10 over the internet.

The backup starts automatically and on the status page via localhost:55414 it shows “Indexing” under the “Last file backup” column.
Under “Activities-Show Log” it only shows “DEBUG Connecting for filelist (async)…” since 3 days.

I have already restarted the local Urbackup server on my Notebook via Windows services but after that the same behaviour.

Is there something special that I have to take into account if I want to backup a remote Linux machine to my local Urbackup server on Windows 10?

Thank you.