Try going into your dvr and under internet or network see what the ip is and what the port is for http access.
then use those to access it. I am not sure of your dvr's software, but you might need to enable ActiveX in your IE.
Open Internet Explorer.
Select the Tools menu and then select Internet Options.
Click on the Security tab at the top of the Internet Options screen.
Click on the Custom Level button as seen below.
This will open the Security Settings - Internet Zone screen. Scroll down the Settings list until you reach the settings that enable active X controls. The following two settings need to be set to "Prompt" or "Enable". NOTE: I recommends setting these values to prompt as seen below. This is much more secure than automatically downloading Active X controls from any website that you happen to browse to.
Download unsigned ActiveX Controls
Initialize and script ActiveX controls not market as safe for scripting
When you are done. Press OK.
Then OK again to save those settings. Windows may ask you to also confirm that you want to change these settings. Confirm.