I did a mistake and cloned github as https:
$ git clone https://github.com/apache/incubator-nuttx
Then after trying to submit a commit is was failing to accept my password:
$ git push origin master Username for 'https://github.com': acassis Password for 'https://acassis@github.com': remote: Invalid username or password.
To error was happening because the https is not the right repository to authenticate with your SSH Keys.
After spending some minutes trying to figure out what happend I found the solution:
$ git remote set-url origin git@github.com:apache/incubator-nuttx.git
This command will change the repository URL to use the SSH address.