The “Communication to Server Failed” error appears when registering to DDNS?

What are the default IP address of the IP cameras?
July 20, 2017

The Preferred DNS Server should not be blank and a public DNS server assigned. A public DNS server to input is Google’s free DNS Server 75.75.75.75 or 4.2.2.2.

For detailed information, please view the relevant technical bulletin.
Technical Bulletin HiDDNS Troubleshooting
Technical Bulletin Remote Access DVR&NVR with HiDDNS v1.1