Assegnate 5 su 5 stelle

Had this installed for a few months now, it works like a dream.

It doesn't work in Thunderbird! Assegnate 1 su 5 stelle

This doesn't work in Thunderbird! It says: „An error occured” when I try to set it up. The credentials I enter are OK, as I can connect with them on the FileSwap site, but it doesn't let me connect it to Thunderbird. Does somebody know why?