Plugin not loading

You are using the block editor (Gutenberg)? The block editor has a shortcode block, but the shortcode should also work in a text block.
Could you post a link to your page, so that I could check it myself?

WPBakery
https://pc-partner.be/domeinnaam/

It looks like the short code is used twice on that page.
If that is intended enable the “Multiple use” option in the general settings.

Hi,
It is only once now, same result.

The jQuery of your theme seems to produce an error: https://prnt.sc/vrsfcx
Since the domaincheck plugin uses jQuery too, this error could prevent it from working.

Mmm ok to bad. Thanks