Is there something worng with the filemanager?

[wasik405]

Welcome back.
If you are uploading multiple files, then you should use an FTP client like FileZilla online file manager isn’t great at doing it -

How to upload files with FTP

The best and most reliable way to upload files is to use FTP. To upload files with FTP, you will need to following: Your FTP username Your FTP password The FTP hostname An FTP client You can find your FTP username, password and hostname in the client area under the FTP Details section. The FTP password is the same as your hosting account and control panel password, which is different from the password for the client area. If you like videos better then text guides, you can find one at the bot…

@Savvas

When I edit a file, the changes are not shown immediately.

It sounds like a browser cache, please clear the browser cache by pressing a few times Ctrl + F5 while viewing your website.
If that doesn’t help (because some browsers are stubborn) then follow these instructions:

How to clear your cache (And cookies) on any browser - A simple guide - The...