Are you adding the accounts as new or existing. Since the accounts already exist, you should be using existing account. (It means "existing on the server", not "existing on the phone".)
(And I didn't think of what hallux posted while I was typing this. Make sure you've updated your email app.)
Having deleted most of my apps to make room to download Android update, the only difference in outcome is having added existing Gmail account, I get a blank screen with Sigh in in the top r-h corner ( before I was getting a dead web-link).