How do I fix the "SenderIDMismatch" error when sending push notifications to Android devices using the Pushwoosh Expo plugin?

FCM returns SenderIDMismatch when the device's push token was issued by a different Firebase project than the credentials Pushwoosh uses to send. It is a project-mismatch error, not a value you type into Pushwoosh — with the Firebase Cloud Messaging API (V1) there is no Sender ID or Server Key field in Pushwoosh any more.

In an Expo project, check the following:

1. One Firebase project everywhere. The google-services.json you point Expo at (expo.android.googleServicesFile in app.json) must belong to the same Firebase project as the service-account JSON private key uploaded in Pushwoosh (your project → Configure platforms → Android → upload the JSON private key from Firebase Project settings → Service accounts → Generate new private key). If you switched Firebase projects, re-upload the key and rebuild.
2. Package name matches. The Android app registered in that Firebase project must use the same package name as expo.android.package.
3. FCM API (V1) is enabled for the Google Cloud project (console.cloud.google.com/apis/library/fcm.googleapis.com).
4. Re-issue stale tokens. Tokens minted against the old Firebase project keep failing — reinstall the app (or clear its data) on test devices after re-configuring, so the SDK registers a fresh token.
5. Correct plugin wiring. pushwoosh-expo-plugin is a config plugin applied at prebuild; the runtime SDK is pushwoosh-react-native-plugin. Install both, add the config plugin in app.json with your Pushwoosh API token, and initialize at runtime with the app code only:

   import Pushwoosh from 'pushwoosh-react-native-plugin';
   
   Pushwoosh.init({ pw_appid: 'YOUR_PUSHWOOSH_APP_CODE' });
   Pushwoosh.register();
   

   There is no project_number parameter, and pushwoosh-expo-plugin exposes no runtime init().