change domain mail stoped working

[blackicerage]

hey i had a account setup useing a subdomain on my server then they got a domain so i change there subdoamin to there full domain But for some reason they can't send mail anymore useing smtp

Ie from outlook they can't send mail but tehy can recieve it i restarted our mail server had a general poke around but i am baffled :/ any help / idea's ?

Thank's

Brendan

[blackicerage]

n/m ended up being the user ^_^