My Gmail app that I have installed in my Android 2.3.5 phone has stopped receiving or sending new emails since the last couple of days. What can I do to fix this synchronization issue? Any suggestions?
I've had the same problem since upgrading my ROM. The solution i'm going to present will lead to the loss of unsent emails, so copy them to somewhere.
You have to clear the application data. To do that you go to:
Settings > Applications > Manage applications
look for Gmail and Clear Data
It will synchronize again with Gmail servers and the problem should be solved. Send a test e-mail to yourself.