Azure Active Directory
At the time of writing this blog post, the BOT framework is still in preview so things are subject to change! However, if you already played with it and tried to enable the Teams Channel for one of your BOTs, you’ll see that it behaves differently than for the WebChat Channel.
If you happen to encounter the error mentioned in the title of this post which is something that bugged me for a while...it might be due to a wrong sequence of actions. As you might know, when creating a custom application that needs to access an Azure Active Directory with the Graph API, you need to grant permissions to the App, in the configuration page of the App or through PowerShell.