I had to change my pop3 password. I changed the password in Evolution, it asked me for the password next time it tried to get mail. I turned off “save password” and next time it checked for mail, it asked me for the password again. I turned on “save password”, entered the new password and checked the mail.
The next time Evolution checked for mail, it asked me for the password again. It hadn’t saved the password.
Ubuntu saves passwords for everything in the same folder. In Ubuntu, under Applications -> Accessories -> Passwords and Encryption Keys you’ll see the pasword folder.
Open “Passwords: Login” and you’ll see a list of things that require logins. There will be a login key for the email address you’re having trouble with. Delete it.
Next time Evolution gets mail, it will ask you for your password, but this time it will remember it.