Web Compatibility Support • Re: Can't pass XDA Forums bunny security check

Or could it be some setting in Pale Moon

A possibility could be HTTP/2 being disabled (network.http.spdy.enabled.http2 in about:config), forcing HTTP/1.1 to be used for all sites like I've done. It tends to trigger a captcha from Cloudflare. You might be able to avoid the captcha while keeping HTTP/2 disabled by using a SSUAO that doesn't have Mozilla/5.0, but YMMV.