Beryl+ ISP box + VPN

Hello guys,
So i am a newbie and you will find out by my schematic
So I have a beryl router

My idea to my setup is explained here:

So I connect ISP router ---- Beryl --LAN1-- ISP TV box. —LAN2–(VPN) tv

My problem here is the ISP tv box, I already activate IGMP but it doesn’t work. The box works for about 10 seconds and then show a notification “no signal”
Already tried IGMP v1, v2 and v3

I think this might be a simple thing but I don’t have the knowledge, and I try it, believe me.

So ? any ideas ?

Is the ISP TV box the kind that connects directly to a TV using a HDMI cable, or does it stream to tablets/smartphones/TVs over wifi or Ethernet cable?

I do not work for and I do not have formal association with GL.iNet

Use VPN strategy ( VPN Policies)to solve your problems, set IP mode, all Chinese IPs are directly connected, without proxy, so that TV can watch domestic direct connection, ISP TV box can directly use the channel when needed, the advantage of this is that domestic and foreign traffic is divided, and the speed is fast,reduce router overhead
使用VPN策略來解決你的問題,設置IP模式,中國IP全部直連,不走代理,這樣電視看國內的直連, ISP TV box需要時直接走通道,這樣的好處是國內外分流,速度快,減少路由器的開銷

Do you have any update according to t he replies?