TMG 2010 Firewall blocking Emails in Outlook 2007

All,
 I am currently using Outlook 2007 for email which uses 
POP3/SMTP for incoming and outgoing mails respectfully . I recently installed 
and configured Forefront TMG 2010 firewall on my network. Web Access Rule has 
been configured and all machines on my home network can get on the Internet 
fine. I have confirmed that the POP3 and SMTP settings are correct. They've 
been working fine before I installed the TMG 2010.

Now the problem is when I tried to send email from Outlook 2007, I receive the 
error:

Error message : 'Cannot find the e-mail 
server. Verify the server information in your account properties"

Now I cannot send and cannot receive any e-mails.

I have even created another access rule for POP3 & SMTP from the External network to the Internal 
network and this thing is still not working.
Any help will be appreciated very much.

Thanks,

Ahmad Ali