El origen remoto ya existe
git remote remove origin
Mysterious Mandrill
git remote remove origin
//fatal: remote origin already exists.
git remote rm origin
git remote add origin [email protected]:username/myapp.git
git remote rm origin
git remote add origin [email protected]:username/myapp.git
git remote set-url origin https://github.com/your/repository
git remote remove origin
#solved
$ git remote set-url origin [email protected]:ppreyer/first_app.git