Event messages which couldn't be processed are moved to Graveyard for further analysis. There are various reasons why an event message couldn't be processed.
You can go to "Graveyard" section and understand the problem using "Cause of Death"
- no permission : The api token used has no permission to post events
- invalid body: The payload sent is invalid
- invalid environment: The environment sent is invalid
- another messages exists with message_id: When a message_id is sent by you, it should be unique