[Exim] cannot send but can receive

Hi,

I'm kind of new to exim and I spend the whole night trying to configure
it....
It's now at a state that it is able to receive mail but it can't send..

When I send a message to hdcool@??? with the server it doesn't
arrive but mailq shows me it's waiting to be sent...

I can receive mail from everywhere on the net, but I can't send..

I did eximconf and chose option 1 : standalone internet server with direct
smtp

please help me,

yours sincerely,

hdcool