help with google account

[eddie Sim]

hi all
i tried to add a google account to accounts and sync on my phone . but when i put in my log in details it says username and password do not match then it says to recover your account information go to google accounts on your computer. but when i log on to google it's ok even on the phone. all i know is that i did something with the security settings with my google account on my pc but can't remember what i did

regards
eddy