Perhaps the Heroku git remote address is somehow broken.
You could first try to access Heroku directly by performing host heroku.com
and ssh git@heroku.com -T
and see what that yields. Like this: Getting error while trying to push to Heroku
With host heroku.com
you should get something like:
$ host heroku.com
heroku.com has address 50.19.85.132
heroku.com has address 50.19.85.154
heroku.com has address 50.19.85.156
heroku.com mail is handled by 10 aspmx2.googlemail.com.
heroku.com mail is handled by 10 aspmx3.googlemail.com.
heroku.com mail is handled by 10 aspmx4.googlemail.com.
heroku.com mail is handled by 10 aspmx5.googlemail.com.
heroku.com mail is handled by 10 alt1.aspmx.l.google.com.
heroku.com mail is handled by 10 alt2.aspmx.l.google.com.
heroku.com mail is handled by 10 aspmx.l.google.com.
Then try fixing your .git/config file, with:
git@heroku.com:your_app.git
Like this: Can't push to existing live heroku app on Cedar Stack
If those two don't help, then could be something more complex.