This can be useful information when debugging what happened to a notificaiton.
Recently there was a discrepancy between the failure type used by each provider for a particular number, this logging would have helped.
There are three authentication methods:
- requires_no_auth - public endpoint that does not require an Authorisation header
- requires_auth - public endpoints that need an API key in the Authorisation header
- requires_admin_auth - private endpoint that requires an Authorisation header which contains the API key for the defined as the client admin user
