How to change permissions (ACL) for the Messaging service

I am getting the following error when using the REST API : {“code”:5008,“message”:“User has no permission to subscribe”}

How do I verify/change the user’s permissions in order to allow the subscription?

    Login to console and select your app. Click Messaging and select the channel in question. Click the red Permissions button in the upper right corner, check the effective permissions for the roles/users for the channel

Thank you for the info.