expo: Android push notifications failing with: ProviderError: There was an unknown error with the FCM server.

Summary

Some of the push tokens registered by my apps are failing without any change to the keys involved. Example key with an issue: ExponentPushToken[Xs-Wk0D6aliFvXGvjU-doE]. The full error: ProviderError: There was an unknown error with the FCM server. See this error's details for more information.. Seepush notification tool.

Note: feel free to ping that token.

Managed or bare workflow? If you have ios/ or android/ directories in your project, the answer is bare!

managed

What platform(s) does this occur on?

Android

SDK Version (managed workflow only)

40

Environment

    System:
      OS: macOS 11.2.2
      Shell: 5.8 - /bin/zsh
    Binaries:
      Node: 14.15.5 - ~/.nvm/versions/node/v14.15.5/bin/node
      npm: 6.14.11 - ~/.nvm/versions/node/v14.15.5/bin/npm
      Watchman: 4.9.0 - /usr/local/bin/watchman
    SDKs:
      iOS SDK:
        Platforms: iOS 14.4, DriverKit 20.2, macOS 11.1, tvOS 14.3, watchOS 7.2
    IDEs:
      Android Studio: 4.1 AI-201.8743.12.41.6953283
      Xcode: 12.4/12D4e - /usr/bin/xcodebuild
    npmPackages:
      expo: ^40.0.1 => 40.0.1
      react: 16.13.1 => 16.13.1
      react-dom: 16.13.1 => 16.13.1
      react-native: https://github.com/expo/react-native/archive/sdk-40.0.1.tar.gz => 0.63.2
      react-native-web: ~0.14.13 => 0.14.13
    npmGlobalPackages:
      expo-cli: 4.1.6
    Expo Workflow: managed

Reproducible demo or steps to reproduce from a blank project

It seems to work on my expo app but not my hardware device. Af far as I can tell this issue is only affecting Android devices (my physical iPad is working fine).

I have re-uploaded my server key with expo push:android:upload --api-key but that had no effect.

I would love to do more debugging but with the rather opaque error I’m not sure how to continue.