Hi @legatusking,
Thanks for reaching out to the Roku Community.
Your Roku device and your phone or tablet must be connected to the same Wi-Fi network. Many Wi-Fi routers today use two signals to provide better speed and coverage. These devices are generally referred to as dual-band routers because they transmit data at the lower 2.4 GHz band and the higher 5 GHz band.
When connecting devices to your wireless network, choices may include more than one network with a similar name. For example, you may see something like MyNetwork_2.4GHz and MyNetwork_5GHz. Confirm that your Roku device and your phone or tablet are connected to the same band and network name.
You can see more here: How to connect the Roku mobile app to your Roku device over Wi-Fi
Regards,
Nimfa