Programattically Get User OAuth Token for Subscriber Notifications

I am using this script to test things:

curl --data "client_id=smwpepmr7s3yt9gqwlz628b2e4tww8" \
     --data "client_secret=<client_secret>" \
     --data "grant_type=client_credentials" \
     --data "scope=openid" \
     https://id.twitch.tv/oauth2/token

The output looks like this:

{
    "access_token":"REMOVED ACCESS TOKEN",
    "expires_in":5045536,
    "scope":["openid"],
    "token_type":"bearer"
}

However, when I try to use the “access_token” to log in, it doesn’t work. Should I be using a different “scope”? Am I using the “access_token” incorrectly?