Setting Up Your In-App Reward
In order to set up server-to-server callbacks, you will need to email Unity Ads support.
In your email to support, include your app's Game ID and the Callback URL from the Configure Unity Ads dialog. In their email response, they will include a hash key, which you should place in the "Shared Hash Key" field below.
Click "Save Changes". Your app is now configured to use server to server callbacks for Unity Ads.
Example email to UnityAds support:
Unity Ads Support <email@example.com>
Please enable Server to Server callbacks for the following application: