AJAX wp_insert_user WORKS but responds with “The site is not enabled”

I have a form on my site which has an AJAX event attached. The AJAX event seems to be working up until I call the wp_insert_user function, I don’t understand why but when I put a wp_send_json_success before the function it works, but straight after, even just returning some text I receieve a “The site is not enabled” response.

Gutenberg: Block validation Failed Richtext undefined

I am building a custom block to add a youtube-video as a background-video that autoplays and infinite loops when you visit the site. To make this happen the user needs to get the video-link and playlist-link (for the loop) and put it into the 2 Richtext input fields I created in the block. Once that is done the video will start playing alredy in the backend to get a better view on how it will look on the site. Now when you save the Block the code will be generated on the frontend as expected but as soon as you refresh the backend page the block will be broken and the following message will be displayed in the console: