I have got Live Mail and have successfully been able to install two own domain names email accounts but with the third I just can't do it! I have reinstalled, repaired etc and have tried to do it from my hosting server both automatically and manually.

I can send and receive from the new one to other accounts on Live Mail and can also send to my Yahoo email but cannot reply to them. I get this message from Yahoo:

No MX or A records for (account name)

I have deleted the account various times both on Live Mail and on host server then tried again from server doing it automatically but nothing helps. I don't know what else to try. Have been doing it for several days now and am getting extremely frustrated. Can anyone help?

Thanks.