Since last upgrade I can't upload files.
Do you know what could be the problem ?
We are having a similar problem following upgrade to Moodle 4.01. Tutors/Admin are unable to upload marked assignments, instead receiving a spinning wheel similar to that shown above. However, Tutors ARE able to upload files as resources, and students are able to upload assignments.
Just wondering are you using a Mac? We have students (Mac users) got the same issue and they can't upload their assignment, but we are not upgraded to 4.0 yet.