Bitbucket Webhook failed with 400 BadRequest "Unable to extract valid event from payload" in RHOCP4

Issue

• When hitting the Webhook URL, the request failed with error 400 BadRequest "Unable to extract valid event from payload"

{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {

  },
  "status": "Failure",
  "message": "Unable to extract valid event from payload: {\"eventKey\":\"repo:refs_changed\",\"date\":\"2020-03-05T16:12:07+0800\",\"actor\":
===========Output Trimmed=============
  "reason": "BadRequest",
  "code": 400
}