why does Norton interfere with Google passwords?

In order to enter credit card account, I had to look up password as Google manager was not loading it.

Using my recorded password from file, it was denied. 

I entered the Norton key for passwords and tried to enter same old password as my "new" choice.

Credit card denied, I should generate a new password. 

I then went back to the site for entry, entered the same old password and had no problems, including allowing Norton to save that. 

SO what happened, why was it so complex?