Hi LittleModernDKApS
You can take a look at any console errors when clicking on the "Save"button.
To do that, just open the Chrome developer tools and go to the Console tab, then click the button and let me know if you see any error.
Also, it would help to read any possible PHP error recorded on your error log. If you don't have it enabled, you can follow these instructions:
https://codex.wordpress.org/Debugging_in_WordPress
Best Regards,
Salva.