Same problem HERE on my milestone 2.0.
HELP, please!!

 

Found this on another message board and it worked!!

There might be an easier way to fix the problem besides the factory reset. When you go
into the phone settings... go to applications then manage applications. Then you can press
the phones menu button and select the filters option. Change it to display all. Then u can
see gmail and gmail storage in the manage list. Try going to them and clearing their data or
cache. This should clear the temporary data from the gmail app allowing it to get a fresh
clean sync.

This wont fix the problem permanently but its easier than a factory reset.

 

I tried deleting the cache on both Gmail and Gmail Storage first and still had the same "no connection" issue. then I deleted the Data from both, it worked. thanks for the suggestion!

 

I'm getting this notice now too. It will try to connect and read "LOADING CONVERSATIONS" for what seems like forever eventually restorting to "! NO CONNECTION" and a button for RETRY. Retry just sets the wheel a spinning again and doesnt solve anything. I have done the recommendation above with going into the settings and clearing the cache. Still nothing.

How do I fix this?