2.4 GHz wireless headphones causes "Insufficient Bandwidth" while watching Amazon Video on Samsung Smart TV

I have confirmed that when I turn on wireless headphones I am unable to watch Amazon Video on Samsung Smart TV. I have this Internet Package:Cox High Speed Internet Premier, DAR3402 Modem (used also for digital phone). Speed Test showed 175 mbs download and nearly 11 mbps upload. I see there is an upgrade modem available but I am not interested in paying a monthly rental fee. What solutions can you suggest?