Run these commands:
chmod 700 .sshchmod 600 .ssh/authorized_keyschown $USER:$USER .ssh -R
cd /.ssh
If it doesnt exist create it in your home directory
mkdir .ssh
add your key with this command
echo "your_key" >> authorized_keys
run these commands where can't even get inchmod 700 .sshchmod 600 .ssh/authorized_keyschown $USER:$USER .ssh -R