BotFramework : Task Module Fetch Not Load The Given Html Page In Url?

Teams Bot Task Module Fetch url not render the html page in my local project folder under pages instead empty tab. i try to hit the 'http://localhost:3978/upload.html' in postman that response returns html page. i have set the static file serve in server,also in manifest validDomians array i includes ****.ngrok.io doamin of local ngrok.can any one help on this..

var taskInfo = {};
  taskInfo.url = taskInfo.fallbackUrl = "https://****.ngrok.io/upload.html"; 
  this.setTaskInfo(taskInfo); 
  return { 
       task:{
       type:'continue',
       value:taskInfo
    }};