First,please go to DVR's Main Menu--Set up--Network,then click 'test' to check if it is OK.
If yes,please try to reboot your Router, then input the IP Address of the Router to IE browser,
you will find the network information of the Router, please enable the DHCP function of the Router.
After that, please try to reconnect the network cable to your DVR, then go to DVR's Main Menu - Setup - Network to tick "Obtain an IP Address Automatically", and click "Apply" to save it.
If this can't help you, please kindly send some pictures for us to check:
1. Please go to DVR's Main Menu- Setup - Network to take a photo
2. Please go to DVR's Main Menu - Information - Network to take a photo
3. Please go to DVR's Main Menu - Information - System to take a photo
As the attachments picture show.
Our service email is email@example.com . If you have anything don't understand, welcome to contact us.