When you install a new D-Link router it is the same thing as creating a new network. Software firewalls and sometimes even the Windows firewall has to be told that you have a new trusted device on the network.
You can either set the D-Link router has a trusted network or it may require the MAC address from the bottom of the router. If you do not know how to change this in your firewall software, please contact technical support for whichever software firewall you are using for assistance in allowing the new router to be a trusted network.
Another reason, your D-Link router firmware version needs to be updated, please go to http://www.dlink.com to download the corresponding firmware update to your router