How to get access to github after change SSH key?

If you changed your SSH key or just created it but still not cloning:

$ git clone ssh://git@github.com/youruser/userproject.git
Cloning into 'yourproject'...
Agent admitted failure to sign using the key.
Permission denied (publickey).
fatal: Could not read from remote repository.

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

Then you could check if your computer key is accepted by github:

$ ssh -T git@github.com --version
Agent admitted failure to sign using the key.
Permission denied (publickey).

Then you just need to force ssh to load your new KEY this way:

$ ssh-add ~/.ssh/id_dsa

DONE! Now you can clone and push your project from and to github.