@ridzo63 

Would there be any error message when the TV failed to work?

Did you set up the static IP address on the TV before?

--if yes, what is the IP setting when the TV is connected to Deco via Ethernet connection?

Thank you very much and wait for your reply.

@TP-Link 

No, it is on automatic ip setting

@ridzo63 

Hi, Did you need IPTV VLAN tag to make TV working properly, such as VLAN ID 600?

https://www.tp-link.com/support/faq/2421/ 

Thank you very much.