Can't create a password for account

I logged in with Facebook, and when I try to add another email or login with google, it asks for existing password, there is none, since it was a "login with facebook"

but when I try to use "login with facebook" instead of a password, i get:

"We couldn't continue with Facebook due to an error. Try again or log in with a different method."

so im stuck with an account that i can't add any emails or login methods to, and can only be logged in through facebook