Cookies are used by the browser to store your preference, log you in without asking for the user name and password each time, or just to store information on you.
When testRTC is executed, the browser is “new” – it has no cookies stored in it, which means that it may require additional steps that you will fail to see running the web service from your own laptop. If you are trying to write a test script, it is suggested you do so by using the private browsing modes available in the different browsers.
In Chrome, this is known as an incognito window. Such a window can usually be opened in the browser by clicking Ctrl+Shift+N.