After successfully cloning my repo from heroku and added another remote
1/ git clone git@heroku.com:[APP].git 2/ git remote add bitbucket ssh://git@bitbucket
you need to add your key to your profile and NOT to a specific repository. follow this: https://community.atlassian.com/t5/Bitbucket-questions/How-do-I-add-an-SSH-key-as-opposed-to-a-deployment-keys/qaq-p/413373