Firebase FCM error: 'InvalidRegistration'

Question

I am currently trying to send a PushNotification to a Device Group using FCM with the help of Firebase Cloud Functions but once the notification is sent, it returns with code 200 but with failure :

SUCCESS response= { multicast_id: 8834986220110966000, success: 0, failure: 1, canonical_ids: 0, results: [ { error: 'InvalidRegistration' } ]  } 

Here is the code I am using to send this notification... what am I missing?

const options = {     method: 'POST',     uri: 'https://fcm.googleapis.com/fcm/send',     headers: {        'Authorization': 'key=' + serverKey,     },     body: {        to: groupId,        data: {         subject: message        },        notification: {          title: title,          body: body,          badge: 1,         },        content_available: true     },     json: true };  return rqstProm(options)     .then((parsedBody) => {         console.log('SUCCESS response=', parsedBody);     })     .catch((err) => {         console.log('FAILED err=', err);     }); 

Where JSON values title, body, subject, message are String

Answer 1

In my case, I was sending notifications to topic ("topics/my-topic"). I was missing prepending / in the starting of topic so I was getting the same issue. SO topic should be /topics/my-topic.

May be this helps!!