That 'Job OK' message will be in the 'Core' window.

That means that the message was successfully received and processed by the core process.

It then needs to be sent on to the destination address by an SMTP client module, either mercuryC (via an SMTP smarthost such as your ISP's) or mercuryE (direct end-to-end delivery). Which are you using?

You will need to check the log for mercC or mercE to see what is happening with your outbound message. 

 Just installed Mercury mail server on my PC.

 I try to send a mail to external email addresses.

 It says that the job was ok.

I assume that this meant the message was sent.

But the recepient is not getting any messages.

I see no errors in the log too.

What could be wrong ? 

Shouldn't I see the message , mail sent successfully or something?