There are a couple of things you can try that might help get you up and running.

Sometimes the invite to houndci-bot will get stuck at 'pending 'on the repo, and if you cancel the invite, then you should be able to activate a repo from Hound. 

It's also possible that your repository might be out of user seats.  If this is the case, then this means that houndci-bot cannot be added to it. However, if you add an extra seat to your repos, then you will be able to activate Hound.

Once you've done these, can you try clicking on the "refresh repo list" on the top right of the main Hound dashboard again, and see if those refresh for you.

NOTE: Double check that your organization doesn't have a restriction on new OAuth apps. These will need to be requested by team members and then approved by GitHub team owners.

If you've tried those and your repo is still not loading, feel free to holler at us by clicking on the chat window at the bottom right of the screen.