"Folder Backup Error" after Crash at 3/30/17

ReadyNAS 102 V6.6.1 + Ready Cloud Client 1.15

After the crash and deleting of all cloud-users end of March I reinstalled the users.

I also had to reestablish the "Backup PC Folder" connections of that users, because there was none.

But when I tried, the Ready Cloud Client told me

"Folder Backup Error

Selected Folder already has a backup job on this device"

but there was none!

So it seems that there are residues of the crash.

I searched in the Win8.1 registry, but coud not find any item with that Folder

And now my question:

Where is the information about that PC-Backup-Folders stored?

And how can I delete that old stuff?

I look forward to your comment and help!