1. Check oAuth app access restrictions
Check to make sure CircleCI is enabled in your GitHub organization third-party app restrictions in your Organization Settings. You can read more about these restrictions on the GitHub docs page.
2. Check the application page on GitHub
You may also need to enable CircleCI on the individual application page. You can do so with the following steps:
- Go to https://circleci.com/account and click the blue check permissions link in the GitHub section.
- This will take you to the app page on GitHub where you can grant permissions to CircleCI in the Organization Access section at the bottom.