Cause
Some event does not exist in the catalog.
What to do
See the events and fix the list.
application/problem+json
{
"type": "https://masnet.com/developers/errors/unknown_event_type",
"title": "Unknown event type",
"status": 400,
"detail": "...",
"code": "unknown_event_type",
"correlation_id": "..."
}