When loading a mediawiki file, it gives an error. What am I doing wrong?

Question

MediaWiki

When you try to upload a file to the server, the site gives an error:
The file you uploaded is probably empty. This may have been due to an error in typing the file name. Please check if you really want to download this file.

• Tried different types and sizes of files. The result is the same.
  
• I can upload files via ftp to the /images folder (does it mean that everything is in order with access rights?)
  
• File uploads are allowed in the LocalSettings.php file
  

Googling, unfortunately, did not help ... Please help!

Answer 1

I can upload files via ftp to the /images folder (does it mean that everything is in order with access rights?)

Not a fact, the web server and ftp can be under different users.