That response sounds an awful lot like customer service at a major ISP, or automatic email replies in helpdesk systems.

It's caused by (some) ad blockers because you call ga() (google analytics) in your javascript which loads through google tag manager which is blocked from loading by default with uBlock for example. This all causing the modal window to not show, leading to a catch error forwarding to your 404 page.

I get it too and I have javascript enabled. The URL is https://www.lawgeex.com/static/Error.html - which isn't too helpful for a 404 ! Also, the error page breaks my browser's back button.