Thanks for raising this to us. Is there a chance you can connect the TV box with Ethernet cable? Devices connected by Wi-Fi may experience slower speeds than those connected by Ethernet cable.
On the other hand, we actually did an article that will help you improve your wireless connection available here.
Easy Steps to Improve Wi-Fi Connection In Your Home
Wireless Channel on your modem - what is it and why should I change it?
Let us know how it will go. Cheers!
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