TMG 2010 policies not work

Good day,

           I am using TMG 2010. I create the following allow firewall policies,

1-     All outbound traffic from internal to  mails only to Designing department

2-     All outbound traffic from internal to Specific websites to HR users

3-     All outbound traffic from internal to external to engineering, Finance etc.

When I try to connect to the internet using client computer and find there is no internet access. When I disable policy no 1 and 2 and allow No 3rd policy to all users, the internet work fine. Can you please help to solve the issue and please tell me how I allow dropbox behind TMG 2010?

Regards,

Imtiaz Latif