Why can’t slack activate the google apps script?

So I am trying to create a Slack app that asks users to choose from two options let say option 1 and option 2. Now sending the options is going fine however if the button is pressed there is no response from slack to the google apps script I am using.

const options = {
    "method": "post",
    "charset" : 'UTF-8',
    "contentType": "application/json",
    "payload": JSON.stringify({
    token: auth,
    channel: channel,
    as_user: true,
    "text": text,
    attachments: [
    {
        "fallback" : "This did not work.",
        "callback_id": randomId,
        "attachment_type": "default",
        "actions": [
                {
                    "name": "ButtionOption1",
                    "text": "Option 1",
                    "type": "button",
                    "value": "Option1"
                }, 
                 {
                    "name": "ButtionOption2",
                    "text": "Option 2",
                    "type": "button",
                    "value": "Option2"
                }
              ]
    }
  ]
  })};
  options.headers = { "Authorization": "Bearer " + auth }
  var response = JSON.parse(UrlFetchApp.fetch(url, options));
  console.log(response)

However when I try to respond there is just a nothing. I can see that the script is also not called.

My doPost(e) function looks like:

function doPost(e) {
  console.log("Started and writing reaction")
  var e_payload = e.parameter.payload;
  var parsed_payload = (e_payload !== undefined) ? JSON.parse(e_payload) : null;
  console.log(parsed_payload)

  try {
    if (parsed_payload != null && parsed_payload.type == "url_verification") {
      console.log("Verify the Challenge")
      var v = JSON.parse(e.postData.contents); 
      return ContentService.createTextOutput(v.challenge); 
    }
  } catch (e) {
  }

If I try to let Slack enable events there is also no response if I want to verify. There appears an error saying:

Your URL didn’t respond with the value of the challenge parameter.

However I can see the script did not run in the logs.