Node.js crashes on heroku after 1 minute, why?

Question

Node.js

Good evening! Tell me why the Node.js script falls, even the simplest one, after one minute on heroku, as I understand it, you need to assign some ports somewhere, tell me where and how. Thank you.
Here is the log:
2017-12-26T15:28:34.303823+00:00 app[web.1]: app started
2017-12-26T15:29:31.552110+00:00 heroku[web.1]: Error R10 (Boot timeout ) -> Web process failed to bind to $PORT within 60 seconds of launch
2017-12-26T15:29:31.552264+00:00 heroku[web.1]: Stopping process with SIGKILL
2017-12-26T15:29:31.691447+ 00:00
heroku [web.1]: Process exited with status 137

Answer 1

.listen(process.env.PORT || 5000)