Cannot log into the game.

[bassesftw12]

as the title says, i cant log into your game, im using another client but i changed the realmlist in the config file. it keeps saying either "convert this account to a battlenet account" or when i try to log in with my gmail that i registered with (idfk why im forced to have a gmail) and it says wrong pass or acc name, or stuck on authentication, help, please?