Relaying e mails

[blueyes]

Hi I had this same problem on my ipad2, and I can't remember how I rectified it, please help someone. I now also have an iPod touch just tried to send an e mail and the following message has come up:-
The recipient .............. Was rejected by the server because it does not allow relaying. Would appreciate a quick response as I am travelling tomorrow Friday and I need it for e mails..thank you Blueyes...