Exception: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel
问题 for firebase notification code WebRequest tRequest = WebRequest.Create("https://fcm.googleapis.com/fcm/send"); tRequest.Method = "post"; tRequest.ContentType = "application/json"; var data = new{collapse_key = "unassigned", to = deviceToken,data = new {body = message,title = title,sound = "default"} }; message to pass for notifaction on mobile var serializer = new JavaScriptSerializer(); var json = serializer.Serialize(data); Byte[] byteArray = Encoding.UTF8.GetBytes(json); tRequest.Headers