What it means
The website can be contacted by Internet Explorer, but Internet Explorer doesn't have permission to show the page.
What you can do
If you should have access to the webpage, then contact the website owner to give your web browser permission to view it. If it is a public website, then it may be that the webpage hasn't been set up properly and contains an error that is preventing it from being shown.
Alternatively, it may be that the webpage is out of date and no longer exists. Try retyping the web address into Internet Explorer.