settings says my email address is invalid

when i go into the mail app, theres a banner at the bottom that says account error. when i click on that it says "cannot get mail. no password provided for email" so i go to settings and i re-enter the password for my email, and then i get a pop up that says "invalid email address" even though it is the correct and valid address. ive tried re-entering the email and password dozens of times but it still wont work. i also went to my email account and changed my password and then tried all that again but still no luck. im vibrating with anger