Try the steps below to wipe your handheld. Once you've wiped your device, set up your email again.
Performing this procedure disables all data services (web browsing, email, etc.) and removes all data (passwords, contacts, etc.) from the handheld. Before clearing the handheld, ensure there is a recent backup of the data.
Thanks budone for the vote of confidence. I agree with the previously mentioned fixes, but before trying those, try simply to delete your email account(s) and set them back up one at a time. Also, you can try to resend your service books. For more on send your service books, see the attached PDF file with this post. If that does not work try budone's fix. After that, then you may have to wipe your device. Make sure you are running the latest OS for your device, also.