Can provide more detail on what you're trying to do? Just saying help with you google account sounds like you need help from google and not Firefox. More detail please.

I read this that the user could only login by using the Google account choice and not via email address and password.

In case of issues, try to login to the Mozilla Account via this website using the email address and password.

• https://accounts.firefox.com/signin
• https://accounts.firefox.com/settings