Windows Mobile 6.5

My HTC HD2 keeps changing my email password from the 11 character password I enter to a 16 character password. I even set up the mail account and did not set a password, when I went back in the 16 character password was there. I have selected the wipe phone info, installed the latest ROM upgrade nothing work. I can receive email but not send as I receive an undeliverable message with 530 authentication required error message.