Originally Posted by SoUnCool
here is what i did to make it work
delete service books for BB insternet service
on gmail application on device, press menu button and select more then select settings, on settings page click menu button and select "reset network settings" this will force GMAIL to make data connection through corporate MDS and not through public MDS (BB internet service)
after that you can register now your device to get all service books back and it still works fine.
Thanks SoUnCool, worked for me too, (Have a 8707 on BES).
When I first downloaded gmail it worked fine for a couple of days.
Then I followed SoUnCool's instructions to get it working again + one extra thing:
I had to de-select Settings> "Always keep me signed in", exit gmail then restart it. It then prompted me to 'allow the https connection'. After connection was re-established, I could reselect Settings> "Always keep me signed in".