External Mail Server (MX Record - Yahoo) - Problem Solved

UPDATE: Problem solved. It took a while for the DNS changes to propagate.

Hello all,

• I have a website in a VPS server hosted by Awardspace;
• I manage the VPS through Virtualmin;
• My domain is feuan.ao and I don't have access to it. The institution DNS.pt manages the .ao domains;
• I want my website to continue in my VPserver at Awardspace but I want my e-mails associated with feuan.ao at Yahoo's e-mail server. I recently bought 50 mailboxes at Yahoo;
• Now I can create e-mails XXX@feuan.ao (at yahoo's control panel). I can send e-mails from the created e-mails, but I cannot receive;
• I have contacted yahoo and they told me: MX records: mx-biz.mail.am0.yahoodns.net Priority: 10 If TTL is required it will be 1 hour or 3600 seconds
• I have changed the MX record in Virtualmin and disabled the "Mail for domain enabled?";
• When I send an e-mail to XXX@feuan.ao, I got: The response from the remote server was: 550 5.1.1 XXX@feuan.ao: Recipient address rejected: User unknown in virtual alias table
• When using this site: https://www.whatsmydns.net/#MX/feuan.ao, I get: 10:mail.feuan.ao for the MX record, which is not the one inserted in Virtualmin.

I'm a newbie, so I please ask any help. Thank you