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.