Welcome to the Roku Community and we appreciate you for reaching us.
How are you powering the device? Is it plugged into the TV USB port, or is it plugged into the wall outlet with the provided cables? In addition, have you tried using another HDMI port on your TV as well as trying your device on another TV to see if you are seeing the same issue?
We also suggest trying to reboot both your wireless router and your Roku device.
Keep us posted and we'll continue assisting from there if needed.