i have a late 2012 macbook pro with outlook 2011 that has been working perfectly fine for 3 months now. today it just decided to stop working everytime i open it i get the following error message

The server for account "accname" returned the error "[AUTH] Authentication failed.." Your username/password or security settings may be incorrect. Would you like to try re-entering your password?

if i say yes and reenter the correct password it doesnt work.

IM USING A POP ACCOUNT

anyone with a solution to this would greatly appreciated.