php - How to receive emails from emails from other servers? -

i'm building simple email application , have done, issue i've far cannot receive emails other domains. explain it:

1. i've domain: domain.tld

2. i want able manage @domain.tld, @anotherdomain.tld (in server), @thirddomain.tld (in different server).

3. my email applications works fine @domain.tld accounts, can create them, send emails , receive them no issues. problems comes when try use accounts using of other 2 domains, i'm able send emails accounts fine, issue appears when try receive them, "no user found" or it, changed mx records domains , set response mail.domain.tld; however, it's not working.

i'm using cpanel btw.

thanks lot!

if code working 1 of domains not other two, i'd guess propagation hasn't completed yet (if have indeed changed mx records). remember not ttl's have same time, therefore might need wait little longer other 2 domains propagate. first of check domains point to. try tool find out domain pointing to: http://mxtoolbox.com/