Talk.google.com and iMessage

I have used Messages on my Mac with no issue for over 3 years. A few days ago, my messages stopped working.

The error message title is talk.google.com Password

The message says 'Messages can’t log in to l...@gmail.com because your login ID or password is incorrect.

I click the Login button and enter my password but the same message pops up. I have tried resetting my password and using a variety of old passwords as well as adding gmail and talk.google.com as an internet account in my system preferences, but nothing has worked.

Thanks for the help.