I'm running a POP3 email address on my 3GS (iOS 4.1) and computer. Both function and connect as normal, but if I check emails from my phone, my mac will be unable to connect, rejecting the password. After about 10 minutes it's fine again. I also get the same problem when trying to use my host's webmail feature. It's a pain in the arse as I frequently find myself wanting to view an email on the computer, but locked out until it resets. Does anyone know what's causing this? Any way to sort it?