Run SADP and see / share the results table.
Your reboot has very likely caused the DVR to pick-up an IP address which is already in use by another device on the network.
You can use SADP to turn DHCP on, which should enable the router to issue a new valid IP address to your DVR.
Then, as per
@Kyle Mc post here reset DHCP to off, to fix the IP address.
I recently installed Ivms-4500 lite on both an iPad and iPhone. I only wish to use them on my home network linked to a Hikvision DS-7608NI-K2/8P with 5 poe cameras. All seems fine with the iPad but although I can play recordings on the iPhone I can't get Live View to work. The Cameras are listed...
www.use-ip.co.uk