Workspace preview error

When I try to preview this code in workspaces it just gives me the error 'Workspace Unavailable This is a preview link for a Treehouse Workspace that is not currently active.

If you are the workspace owner, you can launch it again via the Treehouse site.' Does anyone know what I am doing wrong? (Or if something is wrong with treehouse.)

//Problem: We need a simple way to look at a users badge count and javascript point from a web browser //Solution: Use node.js to perform the profile lookups and serve our template via HTTP

//1. Create a webserver

const http = require('http');

const requestListener = function (request, response) {
  response.writeHead(200);
  response.end('Hello, World!');
}

const server = http.createServer(requestListener);
server.listen(3000);

//2. Handle HTTP route GET / and POST / i.e. home //if url == "/" && GET //show search //if url == "/" && POST //redirect to the user name

//3. Handle HTTP route for GET /:username i.e. /calebnewell //if url == "/....." //get json from trehouse //on end //show proflie //on error //show error

//4. functionn the handles the reading of files and merge in values //read from file and get a string //merge values into a string