There are cases where the cPanel file manager cannot detect character encoding. It may be stuck showing a message such as:
Detecting character encoding for “wp-config.php”

You can fix this by turning off character encoding verification dialog and selecting your encoding when editing the file. You can do that by doing the following:

1. cPanel File Manager Click Settings in the top right
   
2. Check Disable Character Encoding Verification Dialogs
   
3. Click Save

In the future, you must select the appropriate character encoding for files from the cPanel file manager when editing.