Recently GitHub has made changes to their web hooks...
1. Your Webhooks need to be URL-encoded now. In the past, you could get away with it and GitHub would handle the url-encoding themselves. No longer.
2. All webhooks are now by default monitoring/tracking only push events. If you have other events, you need to use the GitHub hooks API.
The best way to make these changes? Use Chrome's Dev HTTP client: https://chrome.google.com/webstore/detail/dev-http-client/aejoelaoggembcahagimdiliamlcdmfm?hl=en
a. Add a Header with Authorization: token <token>where <token> represents your OAuth token for GitHub.
b. Change to use https://
c. Set to api.github.com/repos/<your GitHub owner>/<repo name>/hooks
d. Grab the webhook ID in the JSON response.
c. Set the JSON payload to be add_events and push like the following: