Old Igo TVs do not support Google Assistant or Alexa natively. They lack the necessary cloud certification. You would need a Logitech Harmony Hub (discontinued) or a Broadlink RM4 Pro to bridge the gap.
Your old Igo TV likely has a power-saving feature that turns off network remote services. On the TV, go to Settings > Network > Wi-Fi > Advanced and disable "Suspend network when sleeping." Also, assign a static IP to your Igo TV via your router’s DHCP reservation table. Igo Tv Old Models Remote App-
Even with the right app, old Igo TVs are notorious for connectivity glitches. Try these fixes: Old Igo TVs do not support Google Assistant