How to View Firebase Notification Delivery Reports?
You can rather go to the Google cloud console to check messages sent. Select period from available options on top right of the page.
https://console.cloud.google.com/apis/dashboard?folder=&organizationId=&project=[project-name]
As seen in the Possible Duplicate Post I linked, there is currently no available reports for FCM, other than what can be seen in the Firebase Console (if you sent the message using the console) and using the Diagnostics/Statistics tool in your Play Dev Console.
There is no API that retrieves these FCM log details as of the moment. However, there's been a recent improvement in the Firebase Notifications console where stats (sent count only for now) for messages sent using the FCM API is included in the Firebase Notification console stats. From my answer in the similar post:
As of August 2018, stats for messages sent using the FCM API are now visible from the console. From the Cloud Messaging section, click on the Reports tab. From there, you will be able to filter by message type (
notification,data, and all)
It would seem that the Impressions and Opens are still only available for messages sent using the console. But Sends for sure now counts the messages sent using the FCM API.
Reference: https://firebase.googleblog.com/2018/08/in-app-messaging-crashlytics.html
The delivery report added to the FCM:
Received (available only on Android devices) — The data message or notification message has been received by the app. This data is available when the receiving Android device has FCM SDK 18.0.1 or higher installed.
https://firebase.google.com/docs/cloud-messaging/understand-delivery#message-delivery-reports
Our findings: In order to view statistics for Data messages, the data messages will need to include an analytics label. Check to make sure that these are included. It is just a label, https://firebase.google.com/docs/cloud-messaging/understand-delivery#adding-analytics-labels-to-messages so even without the analytics label, the message should still be sent. It just won't be tracked by their reporting. Data messages do not automatically generate a notification though. Different app states and message types will have different message receiving behavior. A data message should be received in onMessage or setBackgroundMessageHandler for JavaScript clients. Try checking these callbacks to see if the message is received there. I'd highly recommend checking out the quickstart, which should be working fine. You can use it as a base to build off or reference to compare with your app to identify potential problem areas. So our understanding is that it needs to be handled properly on the mobile end, https://firebase.google.com/docs/cloud-messaging/js/receive (though this is the javascript client, it will still apply to mobile).