UPD!
When I upload a file, it is actually created in the folder */files/contexts/1/library, but it is empty (0 bytes). The file name changes (filename-MAR.*, filename-PER.* etc.). But then everything happens as described in previous posts.
UPD!
When I upload a file, it is actually created in the folder */files/contexts/1/library, but it is empty (0 bytes). The file name changes (filename-MAR.*, filename-PER.* etc.). But then everything happens as described in previous posts.