GitHub repo collaborator unable to trigger builds via API

As the title says, the user is listed as a collaborator in GitHub, using a private auth token, but it’s getting a permission denied when trying to trigger a job/build via API.
Is this a known limitation?

Do they have write access to the repository that they’re trying to trigger the build from? They will need to login to CircleCI and create a personal API token, as well as having write access to the repository.