[Solved] Carbonio CE on Ubuntu 20.04.3 LTS minimal

Hi, I have installed Carbonio CE, working all .

After I want install "files" ...I followed the procedure, all ok...now have error in upload file: unexpected TOKEN o in JSON at position 1 

This error (yellow) appears on the client screen when trying to upload a file

Any advice on how to solve it?

thank you

Cal.