I've had my pop3 mail coming to my phone for a month now. It's been working just fine...Yesterday I noticed my phone didn't recieve any new messages. Get to my desk..have messages there. Turn phone off then on...and messages finally deliver. wtf?
Could be a network registration issue. I have those occasionally. If you know you have emails not being pushed, a) restart your phone, b) batt pull, c) resend service books. normally a) will fix it