The question is I can upload PDF but its impossible upload videos.
This videos are in MP4 iin a standart format. it shouldn't be a problem,,,
Web service is LiteSpeed - version of???
At the root of your web space you have a WordPress (WP). WP uses lots of .htaccess files and redirects which are heirarchcal ... 1st one seen rules the roost for any/all directories/scripts below it. That's if LS version allow use of .htaccess files. Your moodle is in a subdirectory of the site and thus could be under control of an .htaccess file meant for WP/LS.
Suggest looking at LS error logs to see if you can't find an issue.
I don't host anything with LS.
So you might need to refer to LS docs somewhere.
? https://docs.litespeedtech.com/
'SoS', Ken