Live tv doesn't work properly

I have plex media server installed (Version 1.13.0.5023) in a QNAP TS-453 PRO 8GB. And almost everything works perfectly. By the way, I have a switch to which the PMS, HDhomerun connect, the nvidia shield, and a set top box are connected. I have configured IGMP snooping mainly for the set top box that performs multicast. The switch in turn is connected to an ASUS rt-ac87u router also with IGMP snooping.
I have several clients at home, Apple TV 4, Nvidia Shield Tv, Ipad; I haven't been able to make Live TV work properly though the DVR has. Channels operate with occasional outages and take time to load when you change from one to the other. I have tried another app called(CHANNELS on apple TV), and it works perfectly with HDhomerun connected to switch or by WIFI..
Could there be a configuration error on the PMS? Or a network configuration error? Is there anyone that Live tv works perfectly well for?
I have the plex pass, and I am very happy with the application. The problem is that I don't see any improvement in the last few months regarding LIVE TV feature.