Github and push a repo

I tried to push my code to github I on mac:

git push origin master
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Thank you

Have you set up git to link with your GitHub account?

Also, is it your repo you’re pushing to?

I did the tuto above, I push my own repo, I cloned and do some commit.