This could be any number of things:
Is this in a lab environment or over a live Internet connection? If it is the latter, then is is possible that your ISP is blocking ports 80 and 443.
What client are you using to access your webserver?
Also, is your webserver accessible across/from the Internet?
This doesn't have anything to do with the resolution. If your
webserver is accessible, maybe I can remotely connect to it
to investigate what's happening - if you're open to this of course.
Standing by ...