error: src refspec master does not match any error: failed to push some refs to 'https://git.heroku.com/feedmychildrenliberia.git' code example

Example 1: git push heroku master error: src refspec master does not match any error: failed to push some refs to 'https://git.heroku.com/write-any.git'

git push heroku HEAD:master

Example 2: error: src refspec master does not match any error: failed to push some refs to android studio

git commit -m "initial commit"
git push origin master