How can we re-write the same C# code as per Zoho deluge?

Question

I am working on a Cliq extension and need some help in re-formatting the C# script to Zoho Deluge script. I need to read response sent by a website and post the parameter with 200 OK status code.

if(!string.isNullOrEmpty(validationToken))
{
  Console.WriteLine($"Received Token: '{validationToken}'");
  return Ok(validationToken);
}

I am trying to subscribe to Microsoft Graph change notifications. After I call the API to create the subscription, Microsoft Graph sends an validation token which I need to pass back to validate the notification URL. But, when I post the validation token, I am getting an error.

The initial API call

data.insert("changeType":"created,updated");
data.insert("notificationUrl":"https://cliq.zoho.com/api/v2/bots/testbot/incoming?zapikey=1001.d2067fe4b9b15aee1a542e4c6b6d40ca.efb4c86660bd487e511eeae596d4f3a2");
data.insert("resource":"/me/mailfolders('inbox')/messages");
data.insert("expirationDateTime":expire);
data.insert("clientState":"SecretClientState");
data.insert("latestSupportedTlsVersion":"v1_2");
Api = invokeurl
    [
        url :"https://graph.microsoft.com/v1.0/subscriptions"
        type :POST
        parameters:data.toString()
        connection:"microsoft"
        content-type:"application/json"
    ];

Posting the validation token received

token = params.get("validationToken");
decoded = zoho.encryption.urlDecode(token);
data = Map();
data.put("Status code","200");
data.put("Response body",decoded);
Api = invokeurl
[
  url :"https://graph.microsoft.com/v1.0/subscriptions"
  type :POST
  parameters:data.toString()
  connection:"microsoft"
  content-type:"application/json"
];

The error I'm getting

{
  "error": 
  {
    "code": "InvalidRequest",
    "message": "expirationDateTime is a required property for subscription creation.",
    "innerError": 
    {
      "date": "2023-03-01T10:05:01",
      "request-id": "d0566e86-c9a2-4208-846d-4c0965bfc96a",
      "client-request-id": "d0566e86-c9a2-4208-846d-4c0965bfc96a"
    }
  }
}