All, like many others I hit this problem last week. Deleting the mail account and adding it again clears the problem for a short time. Today I figured that the last thing I did before the problem started each time was forward an email. So I tried some testing here and it appears either forwarding or sending a new email causes the sync to break. If you then delete the forwarded/sent email from sent items, it appears to clear the problem and it starts syncing again !!
At the moment my emails are showing..but I have had to delete my account from Gmail and then reinstate it twice today. I will check on the web page before doing this next time and let you know.
I have the same problem. I deleted the account from my phone and re-instated it and all the e-mails appeared. Thought that had solved it - but no - subsequent e-mails did not appear. I appears that the only time it will sync is when it is being installed. Gmail appears to be syncing as it reports the time the last sync process was executed. So, I assume the BT end of the process is not behaving.
