Try this and see if it will reset the router and allow you access, no guarantee that it will work on
your router, have work on other D-Link routers before.
Leaving the power cable connected
And removes all ethernet cables and the phone line from the router
“Do Not Remove The Power Cable”
Press and hold down the reset button for 15 seconds
Remove the power cable from the router while still holding down the reset button for another 30
seconds with the power cable removed
While still holding down the reset button plug the power back into the router
Wait for another 45 seconds and then release the reset button.
Wait for another 10 seconds and remove the power cable
Keep the router unplugged for 60 seconds then plug back in the power cable and all other cable and
check if you can access the router
If still no joy, you can bin it or return it to D-Link, you may get a free replacement or they'll sort out