E-mail problem

I have two AOL e-mail addresses on my 520 and one of the works perfectly and the other which is my primary address will not let me send e-mails, as it keeps asking me to update my account information due to my AOL account info being incorrect, which I presume is my password and username? When I type the correct username and password in for that address and press save, the same page reappears, it's driving me mad!! any ideas please?

Have you tried uninstalled the mail accounts, then bringing back the primary account first to make sure there are no conflicts? Then if it works properly, recreate the 2nd account and see if it still works or has issues again.