If your referring to access from the LAN side then you can't use the WAN IP address:80 to access it from the LAN side. For LAN access I presume that using the DVRs LAN IP address would be only needed...
what's the solution to get access in the same network WAN IP address:80 because when to access using smartphone with this ip in another network when I'm away or I'm at home I can't change it everytime from local ip to public ip everytime I exit my home and vice versa
in another website some people say the problem that block access from ccess in the same network WAN IP address:80 you need to it was just a WAN Service configuration called "Bridge PPPoE Frames Between WAN and Local Ports."
the answer from another website
The problem that not even the D-Link support was able to settle in Brazil, it was just a WAN Service configuration called "Bridge PPPoE Frames Between WAN and Local Ports."
Follow the path: ADVANCED SETUP > WAN Service, then click the "Edit" button from the WAN service you want to change, then NEXT then NEXT again and there are some checkboxes on the screen.
One is "Bridge PPPoE Frames Between WAN and Local Ports." Check this checkbox and click "NEXT" 3 times more and finally click the "Save / Apply" button. Finally, just reboot the router.
With this option enabled I can access my web server, located in my home, from the Internet!
but I can't find those option in my router dlink dsl-2640b