When your callback URL is secured, you will need to provide Authentication Token which will be passed along in the Request Header
Token without Expiration
Token with Expiration
OAuth 2.0 requires an authentication token, which is issued by an authorization server, in order to connect to your webhook endpoint. The authentication token is checked by the receiving endpoint when accepting the HTTP request.
You need to input the ServerAuthenticationURL which will return a token which can be used to authenticate to your callback URL.