I'm facing a weird problem with some websites. In my network nobody is able to access a particular website, whereas that website is up when I checked it at http://www.isup.me/.
This happens quite frequently in my network. Not only this site, it happens with some other websites as well. But after a day those sites are up again in my network.
What could be the reason behind this? Is there any solution for this issue?
Update: I tried to reach website with IP address by using ping but couldn't successful. I'm using Windows operating system. I tried to access this site on all browsers (chrome, IE, firefox) Our network has a router but we dont have access to it. But I can request my administrator if anything requires to be done.