how to program my remote for a Samsung 43AU8000F. tv using xfinity’s X1 5G internet service to access Broadcast Network, Cable TV, & Roku?

How do I program my remote control for a Samsung television model 43AU8000F using xfinity’s X1 5G internet service to acceess Broadcast Network, Cable TV, and Roku services?

Just yesterday I upgraded to xfinity's 5G service, installed new tv. boxes, a new router, and the xfinity xr15v2-uq remote.

The day before yesteday i could access roku or cable tv by. selectng "source" on the older remote control.

Today "live tv"/cable TV doesnt appear as a choice, roku works ok (why - i do not know), and

the xfinity remote control powers up and controls nothing.

Meawhile a messsage flashes on tv setup.screen remote "cannot pair with tv.."