The domain in the CSR is restricted

Question

While requesting a certificate with domain *.no-ip.org in CSR, SSL Panel returns an error: The domain in the CSR is restricted.

Answer

That is because the customer does not own the root domain and therefore is never able to complete the validation steps. The blocked domains are:
'synology.me',
'now-ip.com',
'dyn.com',
'changeip.com',
'afraid.org',
'freedns.io',
'routable.org',
/\.(dyndns|no-ip)\.(com|net|org)$/