MX record keep being denied

[true3]

Every time I try to set up MX record for email. It says mail forwarding is not allowed for this domain. I purchased my domain from Shopify. So I try to figure it out two days ago. I just reset the DNS and it's still not working. Now it says primary customer account set up in progress domain. I don't think the domain I bought some Shopify was verified How do I verify it. 

[true3]

That would be helpful I would like that please