I have a site in production. It was upgraded from 3.0 to 3.1, and moved from a test server to a production server, with different domains.
Now, I cannot upload files. When I'm in the file manager, the "drop file here" doesn't show, and no errors are given. I haven't logged errors and warnings yet, this is dumb. I will do it after this post and update it with my findings. But, when I change the environment type from live to dev, the "drop file here" appears, and I'm allowed to upload files. The Assets folder was copied from the 3.0 installation and synced. It has the appropriate permissions.
A /dev/build has been run.
In advance, thanks for the reply!
Update: No errors logged.