sarsenbaev
Also, the next thing to check is if that file actually exists in the database. Hover the file URL, copy the key value from the URL, go to the database, go to the _file table, lookup where key equals the key you copied (if no record returned then the file doesn't actually exist), then grab that id, go to the _file_chunk table, and lookup where file_id equals the ID you copied. This should return at least one record. If it returns zero records then that file content doesn't actually exist. If this is the case you'll need to reattach/reupload the file.
Cheers.