I seem to be having problems with Mail on my 3G + wi-fi 64 Gig iPad. It will only stay open for a couple of seconds. it then takes me back to the Home screen. It seems to be receiving new messages, but when I delete them, they reappear in the in-box next time I launch mail. I have shut down the iPad several times and restarted. I have synced the iPad with the Macbook. Doesn't help. Other apps seem to be working. any advice?