iOS 5 MS Exchange Problem on iPhone 4

I have updated my iPhone 4 with the new iOS 5. The only issue I am having is that my email (a gmail account) that I use with Microsoft Exchange keeps giving me a "Password Incorrect: Enter the password for the Exchange account." error message. I deleted the mail account, added it again, and it verifies with all check marks just fine. However, the moment you go to check your email, this message pops up. I don't want to use it as POP due to using gmail calendar instead of my mac one. Does anyone know how to solve this? My password is correct, is entered case-sensitive, and etc. I searched the forums, but the other person solved theirs with just re-adding it which isn't working for me.

Thank you in advance for your consideration and support.