gmail on vodafone

[spitfiredriver]

I am using Gmail and can only send E-mail when connected to wifi.
I am connected to vodafone with a 3g connection and unable to send any thing, what am I doing wrong.

 

[Szadzik]

Are all other applications working over 3g? Can you go to the Market and browse the internet? If not then it probably means you need to set up an APN.