I am able to send the notification to single device, topics and user segment from Firebase Console.

I want to send the push notification to a user segment. I searched a lot but I'm only getting script to send notification to Single User or Topic not to user segments.

I tried the below code

var client = new RestClient(https://fcm.googleapis.com/fcm/send);

var request = new RestRequest(Method.POST);

request.AddHeader(content-type, application/json);

request.AddHeader(authorization, key=mykey);

request.AddParameter(application/json, nn{to : user-segment-name,nnotification : {n    body : test message,n    title : Portugal vs. Denmark\n    },n    priority:high\n}, ParameterType.RequestBody);

IRestResponse response = client.Execute(request);

Response.Write(response.Content); 

And I am getting the response below

{multicast_id:5837227475989925972,success:0,failure:1,canonical_ids:0,results:[{error:InvalidRegistration}]}