At the moment, if you try to set up Git for your deployment but you do not add your SSH key to your GitHub/BitBucket account, when you press the refresh button in order for it to find your branches, it will come back completely blank with no warning. So for new users or users that aren't familiar with Git, they will be left wondering what the issue is...

I propose that you add a warning/alert. For example - "Access denied - make sure you have added your SSH key to your Github account"