Unable to change, save or update language file

-- url of the page with the problem -- : www.paardenmestonderzoek.com/administrat...sk=latest&code=nl-NL
-- HikaShop version -- : 4.2.2
-- Joomla version -- : 3.9.12
-- PHP version -- : 7.3
-- Browser(s) name and version -- : Chrome
-- Error-message(debug-mod must be tuned on) -- : No error message

Hi all,

I am having a strange problem with my language file. I get the message there is a new language file and if I choose to get it from the server and click "save" Joomla/Hikashop appears to freeze up. Same thing happens when I just open the language file and click "save".

It happens with the normal english language file, as well as with my personal dutch language file.

Any ideas?

Short add to the issue above;

When I open the Languages page, I suddenly have a notice as follows;

INSTALL_MISSING_LANGUAGE_IN_JOOMLA

And al my remarks in the Override section of the language file are gone now

Edit: After getting the message above I reinstalled the correct language file. Unfortunately, problem still occurs.