It seems that the issue you're facing is related to an internal server error on Microsoft 365's side. Here are some steps you can follow to resolve the issue:
Try again later: As the error message suggests, this might be a temporary issue. Try again after some time.
Clear your browser cache: Sometimes, cached data can cause problems during registration. Try clearing your cache or use a different browser.
Use a VPN: If there’s an issue related to your geographic location or internet service provider, using a VPN to access the service from another region might help.
Check your account: Make sure you're using the correct account and that it’s not suspended or blocked.
Contact Microsoft Support: If the issue persists, you can contact Microsoft support for specialized help in resolving the error.
If these steps don't solve the problem, the issue might be with Microsoft's servers, and you might need to wait for them to fix it.