Hi August Septimius Krogh,
Thank you for your purchase.

It is not related with version of WordPress because we are using version 4.6.1. on our official website.

Please provide me a temporary WP-admin login for your site where this happens, so we could log in and take a look ‘from the inside’ as that’s the most efficient way to see and resolve the issue. We do not interfere with any data or anything else except for the plugin (in case that’s a production version of the site), and of course we do not provide login data to third party. You can write credentials here just check PRIVATE so nobody can see it except us.

Hi August Septimius Krogh,

Can you change your theme to default WordPress theme so we can see is the issue related to your activated theme.

Also can you disable these two plugins in mu-plugins folder:

Notes and Notes common

because they are causing two JS errors which you can see in your console and maybe bacause of that JS is broken on your whole website.

Hi August Septimius Krogh,

Yes default theme is Twenty-Sixteen. When you change to Twenty-Sixteen can you also disable all other plugins?

Hi August Septimius Krogh,

You don't need to deactivate all other plugins because we founded that it is not working because of your theme. Your theme is causing JavaScript errors that breaks all JavaScript on your page. Because of that our plugins is not working. Now when you change to Twenty-Sixteen I saw in console that you don't have any JavaScript errors on your page.

My suggestion is to:
-Contact theme support to resolve these JS errors, because all other plugins that are using JavaScript will not work.
-Update you theme to newest version
-If nothing of this helps maybe you should consider to change your theme, because theme with a lot JavaScript errors is not good for website overall.