Mail Pro and domain problem

Hello everyone,

Today, I subscribed to a Mail Pro plan. But when I try to add my domain, I have so many problems:

I have a domain from another registar and I enabled CloudFlare on it.

* I verified my property adding a CNAME record, but when I try to add MX records (5 records), the dialogue window does not let me to go to the next step (Button is greyed out).
* I added an SRV record with these properties: Name: @ | Service: _autodiscover | Protocol: TCP | Priority: 0 | Weight: 0 | Port: 443 | Target: pro2.mail.ovh.com

and when I confirm, the panel gives me this error message: An error occurred while changing your DNS zone.

My domain is in not authoritative mode. I want to use it in my GMail account. When I try to add "pro2.mail.ovh.net" as the destination mail server, it says to me that "Operation is in loop".

The guide does not provide me anything and does not explain how to solve problems.
Thanks in advance.