Git Push Heroku Master HTTP Transport Authentication

I am having issues trying to push my app using git to heroku via HTTP. I have run:

$ heroku login

from the command prompt successfully, but when I try to push to heroku, I get prompted for a username and password again with the following message:

remote: ! WARNING
remote: ! Do not authenticate with username and password using git.
remote: ! Run 'heroku login' to update your credentials, then try the git command.

This is similar to what was described in git push heroku master still asking for authentication, but the url in my .git/.config files appears match what is on the dashboard.

I verified that the api key matches what is on the heroku dashboard using:

$ heroku auth:token

I have also tried to regenerate the API key and got the same result. Has anyone resolved this issue with Heroku using the HTTP Git transport?

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