Purge cache from azure devops not working

[neo.he]

I am calling this api to purge web site’s cache,
zones/:identifier/purge_cache
It is working fine in postman.

But I tried to call it from azure devops pipeline:

jobs:
- job: ClearCache
  pool: server
  steps:
  - task: InvokeRESTAPI@1
    inputs:
      connectionType: 'connectedServiceName'
      serviceConnection: 'Purge Dev Cloudflare cache'
      method: 'POST'
      headers: |
        {
        "Content-Type":"application/json", 
        "Authorization": "Bearer ${Token}"
        }
      body: '{"purge_everything":true}'
      waitForCompletion: 'false'
      successCriteria: 'eq(root[''success''], ''true'')'

It always returns

============================================================================== 
Task         : InvokeRESTAPI
Description  : Invoke a REST API as a part of your pipeline.
Version      : 1.198.0
Author       : Microsoft Corporation
============================================================================== 
Request body: {
  "purge_everything": true
}
				Response Code: 0
				Response: An error was encountered while processing request. Exception: {"success":false,"errors":[{"code":10000,"message":"Authentication error"}]}

Exception Message: The remote server returned an error: (403) Forbidden. (type WebException)
				Evaluation of expression 'eq(root['success'], 'true')' failed.
				
Exception Message: Error parsing API response into a JSON object. (type DistributedTaskException)

If I switch to zone-list-zones with same headers, it works fine.

The only differences between these two apis are the end point and POST vs GET.

Could anyone help me out? Thanks.