test fails to complete when I press start test

[nitish]

I have setup webpage test server in AWS and a few agents on my local desktops.
Now when i hit http://webpagetesturl.net/install, I can see all the agents connected.

It's when I enter the url to test and select the test location from drop-down and start test. It fails to load the page.

https://webpagetesturl.net/runtest.php

failed to load the page

please assist as I don't know what could be going wrong here