strange mail problem

[hungtc]

I'm new to DirectAdmin, I have a domain email account [email protected] that always receive email without problem, however, [email protected] does not receive email most of the time, depend on the sender, for example if it is from gmail, then the mail arrive, otherwise an error message showing at the sender "No MX or A records for domain.com". I believe dns is setup properly otherwise [email protected] won't always send and receive emails. There is no spam filter setup.

I'm running DirectAdmin on an unmanaged VPS so there is no support from hosting company. I'd appreciate any idea to help me troubleshoot this problem.

Thanks
Thomas

 

[hungtc]

problem solved, it was the nameserver.