The following list contains reasons why this event was generated:
- If you created the mobile push template by using the code creator, check if the `priority` parameter is in line with the FCM documentation ([Firebase Cloud Messaging HTTP protocol](https://firebase.google.com/docs/cloud-messaging/http-server-ref)). The default values are `high` or `normal`.
- If you received the event with a `message key duplicated` error, it means that there were multiple attempts to send the message in too short intervals. In general, it means that deduplication worked correctly and one message has been sent instead of multiple identical messages.