Microsoft Teams task module with URL not working

Tring to trigger a task module that will display a web page. All I was able to get is an empty Task Module with the title, while the specified height and width do not affect nor is the URL displayed.

The task module fetch handler function:

const { TeamsActivityHandler } = require('botbuilder');
class Foo extends TeamsActivityHandler {
/* ... */
  handleTeamsTaskModuleFetch(context, data) {
    return {
      task: {
        type: 'continue',
        value: {
          title: 'Task module title',
          height: 1000,
          width: 700,
          fallbackUrl: 'https://giltichon.com/bar',
          url: 'https://giltichon.com/bar',
        }
      }
    };
  };
};

I've made sure to list the URL in the apps manifest validDomains but still the URL is a no show...

UPDATE: also added composeExtensions property

App manifest:

{
...
  "composeExtensions": [
    {
      "botId": "***",
      "canUpdateConfiguration": true,
      "commands": [],
      "messageHandlers": [
        {
          "type": "link",
          "value": {
            "domains": [
              "giltichon.com"
            ]
          }
        }
      ]
    }
  ],
  "validDomains": [
    "giltichon.com"
  ]
}