Can you send us a screenshot of what your labkey server looks like (including the address bar) in a web browser?
It might be that you need to add a "/labkey" onto the end of that URL:
it might be that you need to use "http" instead of "https":
or it might be that you need to specify the port number:
or it might be some combination of the above.
Also, some browsers hide the "www." at the beginning of URLs in the address bar, so even though it might look like your web browser is on the page:
it might be that the URL needs to be:
(I believe if you copy the URL out of the address bar in the browser and paste it into notepad.exe you will be able to see the real URL).