CONSOLE ERROR: XMLHttpRequest cannot load http://127.0.0.1:8000/xmlhttprequest/resources/access-control-allow-lists.php?origin=http%3A%3A%2F%2Flocalhost%3A8000. The 'Access-Control-Allow-Origin' header contains the invalid value 'http:://localhost:8000'. Origin 'http://localhost:8000' is therefore not allowed access. -------- Frame: '-->' -------- Check that exact matching is used when comparing a request's originating url and the value provided by Access-Control-Allow-Origin. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". Should disallow origin: 'http:://localhost:8000' PASS xhr.send(null) threw exception NetworkError: A network error occurred.. PASS successfullyParsed is true TEST COMPLETE