Forward mail trafic from ISP (authoritative) to GTM through CName

Hi Folks,

 

Is there any way to forward Mail (MX record) traffic from ISP Authoritative for ABC.com to GTM.ABC.com through CNAME. Actually we are able to forward all A record traffic from ISP to GTM through CNAME but MX record traffic not coming to GTM when we removed MX record from ISP and create on GTM. On ISP site we created CNAME only

 

Please note that ISP is authoritative for our domain (ABC.com)

 

Kindly advise.