How to Resolve Heroku's 'not authorized to access newname' Git error. When you see the 'not authorized to access newname' error, it probably. means that your Git configuration is incorrect. For example, my .git/config file had the following:
 repositoryformatversion = 0
 filemode = true
 bare = false
 logallrefupdates = true
[remote "heroku"]
 url =
 fetch = +refs/heads/*:refs/remotes/heroku/*
Notice the highlighted words. Just change newname to the actual project name and you should be fixed.