Xumo TV through Xfinity: Screen Mirroring Issues

I’m having an issue with my Xumo from Xfinity with the screen mirroring function on the TV. I’m told on your website that I should be able to use the screen mirroring feature on my iPhone in order to cast the screen to the Xumo tv as long as the devices are on the same network. However, when I try and activate screen mirroring from my phone, it doesn’t register any devices. Furthermore, if I try activating it from the TV using the input button, it doesn’t allow me to select the option. I have checked numerous times to ensure both devices are on the same WiFi but it still won’t come up as an option when I attempt to use screen mirroring