My DVR for recording TV programs is not working properly. It only happens after I set up the Deco to be part of my existing network. This means my Deco is connected to another router.

DVR device is a computer capable of digital recording. We can also apply the solution for this case in DVR/NVR that can't record or access a security camera. 

For this case, I tried to contact Technical Support and I was not able to discuss with them the correct setup of my network. They thought the topology is below:

Modem > Main Deco > RE Deco >> A DVR receiver hardwire >> Smart TV

After communicating with them for the 2nd time, they confirm that the issue is because I am using the topology below:

Modem Router(In bridge mode) --- is wired to --- Main Deco )))Wireless to ((( Satellite Unit Deco ---wired--- DVR receiver

Modem Router(In bridge mode) ---wired--- DVR main

Satellite Deco )))wireless((( Smart TV

My Modem Router has multiple LAN ports. I forgot that the main DVR is still connected directly to the modem router, not to the main Deco. After connecting the main DVR to the Main Deco, it started to work properly. 

Solution: They said, we need to make sure that the DVR/NVR and other client devices(DVR receiver and Smart TV) related to them are connected to the Deco network properly. They are communicating thru IP address, if the DVR IP address is different from the client IP address(DVR receiver and Smart TV) , they will not be able to communicate with each other properly.