Not getting Firebase Crash Reports when Upgrade to the Firebase Crashlytics SDK

Firebase sent the following message :- "Note: The Fabric SDK is now deprecated and will continue reporting your app's crashes until November 15, 2020. On this date, the Fabric SDK and old versions of the Firebase Crashlytics SDK will stop sending crashes for your app. To continue getting crash reports in the Firebase console, make sure you upgrade to the Firebase Crashlytics SDK versions 17.0.0+ for Android,4.0.0+ for iOS, and 6.15.0+ for Unity."

I followed the steps given in the bellow link :- https://github.com/a-imai/XamarinCrashlyticsUpgradeSample

1. Uninstall existing crashlytics packages
2. Install new packages
3. Reinstall google-service.json
4. added <string name="com.google.firebase.crashlytics.mapping_file_id">1.0</string> to strings.xml
5. delete <meta-data android:name="firebase_crashlytics_collection_enabled" android:value="false" /> from AndroidManifest.xml
6. Remove Fabric reference from MainActivity.cs i.e delete Fabric.Fabric.With(this, new Crashlytics.Crashlytics());
7. In MainActivity.cs, under OnCreate(), I added small code to crash the app

When I run the app, App is crashing but The Problem I am getting is not able to get crash reported under Firebase Crashlytics. But not every this this is happening, yesterday i got crash reported in firebase crashlytics. But today app is crashing but not getting crash reports in firebase console