Hi James. If you insert the new url in the Admin Panel> Domain> Move domain section, you should receive the success message and we will move your domain within a few hours.
However, if instead of the success message you are receiving an error messages like "Please set a CNAME from community.mydomain.com41 to domains.tribe.so39", it mean that you have not done the settings correctly.
One common mistake is that people who are using Cloudflare forget to turn off the proxy before adding the CNAME, although we have clearly mentioned it in the domain move tutorial.
If you still don't receive the success message, you need to contact our support team by click on the "chat with us" button, as @Viktor Nagornyy33 explained. Our supprt team will assist you and walk you through the CNAME settings and the A record to have all the settings right.