Error 1014: CNAME Cross-User Banned


Hi, I’m helping a guy host his app on his domain, so I’m running it on my VPS. I set an A subdomain on my domain, and my friend made a CNAME redirecting to that subdomain. On his website, it gives the error “Error 1014: CNAME Cross-User Banned”. I don’t want to ban him from making that CNAME. Is there any way to stop this?