I have a client that is moving to a new domain name.
The old domain name is promosource.co.nz
The new domain name is primesource.co.nz
The email server is currently receiving emails for both domains and this works for all sending domains except, any email account sending from the Xtra Domain.
Xtra one of New Zealand largest Domain companies. Their Domain is “xtra.co.nz”
The error when sending via xtra domain is "The following addresses are invalid:"
Also if I send from the Xtra domain to the same email@example.com the email will be delivered successfully. I have discussed the problem at great length with the technical team at Xtra and Compass (the clients ISP) with no resolve.
I have confirmed the structure of the DNS records and made additional changes to see the results. Still no resolve. Can someone please give me some ideas to move this forward?