Cross origin error

[vdidushko]

Bug Report

Description

After executing the following query in browser's console

    cache: 'no-cache',
    credentials: 'include',
    headers: {
      'Authorization': 'Basic XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX'
    },
    method: 'get',
    mode: 'cors',
    redirect: 'follow',
    referrer: 'no-referrer'
  };

  fetch('https://in.elastic.io/hook/5ea6a4c55d7ddd5e75eb4191', request);

it is throwing the following error message:

Access to fetch at 'https://in.elastic.io/hook/5ea6a4c55d7ddd5e75eb4191' from origin 'https://app.elastic.io' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

in.elastic.io/hook/5ea6a4c55d7ddd5e75eb4191:1 Failed to load resource: net::ERR_FAILED
5b62c919fd98ea00112d52e7#/w/58dcfe0f52f01e0019e7484e:1 Uncaught (in promise) TypeError: Failed to fetch

Preconditions

1. Create a new flow.
2. Add Webhook component as trigger
3. Add http reply component
4. Add custom headers to http reply component
   Access-Control-Allow-Origin: "*"
Access-Control-Allow-Methods: "GET"
5. Turn on 'real time' flow
6. Start the flow

Environment

• Great Moraq (development)
• Essos (stage)
• Westeros (production)

Steps to Reproduce

1. Run the created flow.
2. Execute early mentioned query in browser's console with the authorization header as in Webhook step.
3. Observe the error message.

Actual Result

Access to fetch at 'https://in.elastic.io/hook/5ea6a4c55d7ddd5e75eb4191' from origin 'https://app.elastic.io' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

in.elastic.io/hook/5ea6a4c55d7ddd5e75eb4191:1 Failed to load resource: net::ERR_FAILED
5b62c919fd98ea00112d52e7#/w/58dcfe0f52f01e0019e7484e:1 Uncaught (in promise) TypeError: Failed to fetch

Expected Result

Status code 200 OPTIONS

[vdidushko]

Most likely can be reproduced with any authorization method.

[jhorbulyk]

Closing in favor of https://eio.productboard.com/feature-board/2273350-planning-board/features/8357891/detail