I seem unable to set a 'Custom Input Domain'. I've created a CNAME record on the side of my domain host, and it seems to reflect that when querying the domain, but it's stuck at 'Pending' in the Cloudflare interface. I've tried removing it and re-adding it several times with no luck. I've also tried to use the 'Revalidate' function, but again this has changed nothing. What can I do to fix this?