Heartbeat http not providing any ping result

Below is my code. When i check, it always showing summary.up is true. I test using postman i receive 400 bad request

- type: http
  id: my-site
  name: MY Site
  enabled: true
  schedule: '@every 5s'
  hosts: ["https://mysite/mypage"]
  check.request:
    method: POST
    headers:
      'Authorization': 'Basic dXNlcm5hbWU6cGFzc3dvcmQ='
  check.response.method: [200]
  timeout: 16s
  ssl.verification_mode: none

Can you post the entire response from heartbeat? If your site has redirects in place you may want to enable max_redirects: 5 to follow up to 5 redirects. Heartbeat does not follow redirects by default.