Why am I getting an 'InvalidProviderToken' error for my iOS application?

The InvalidProviderToken error means that the authentication token being used to connect to the Apple Push Notification service (APNs) is incorrect, expired, or has been revoked. This prevents your application from successfully sending push notifications to your iOS users.

This can happen for several reasons:

• The APNs authentication key (.p8 file) was revoked in your Apple Developer account.
• The Key ID, Team ID, or App Bundle ID entered in your push provider's dashboard does not match the information in your Apple Developer account.
• You have uploaded a key that belongs to a different application or developer team.

To fix this, you need to verify and update your APNs configuration:

1. Log in to your Apple Developer account and navigate to the Certificates, Identifiers & Profiles section.
2. Go to Keys and check the status of the key you are using for push notifications. If it has been revoked, you must create a new one.
3. Update your settings in your push notification service's control panel. Upload the correct .p8 key file and ensure that the Key ID, Team ID, and App Bundle ID are entered correctly and match your Apple Developer account records exactly.

After saving the updated configuration, the error should be resolved.