Capturing multiple values via extractors regex, how to iterate?

[Thamaraiselvan942]

Hi Team,
In the below template, I captured multiple values via extractors, and I tried to make multiple iterations of the request using payload options. But it shows an error: invalid map key: map[interface {}]interface {}{"message_id":interface {}(nil)}, Please suggest if there is any other option to achieve this case.

id: get-mail

info:
    name: get-mail
    author: arj
    severity: info
    tags: get-mail

variables:
    access_token: "8688"

requests:
   - raw:
       - |
         GET https://test.com/api/accounts/650/messages/search HTTP/2
         Host: test.com
         Authorization: Bearer {{access_token}}

       - |
         GET https://test.com/api/accounts/650/folders/67/messages/{{msgid}}/content HTTP/2
         Host: test.com
         Authorization: Bearer {{access_token}}

     payloads:
       msgid: {{message_id}}

     req-condition: true
     extractors:
          - type: json
            part: body_1
            name: message_id
            group: 1
            json:
              - '.message_id'
            internal: true