Comment 3 for bug 632605

Hm, the error seems to be related to the FTP connection. It is not triggered inside of sbackup. I'll look into it, however I was not able to reproduce the bug so far (FTP access to Strato HiDrive works for me without flaws).

As a workaround you could use the 'legacy' Fuse plugins if they worked for you: https://answers.launchpad.net/nssbackup/+faq/1256