New box new remote wont work

Successfully added Nighthawk wifi modem/router and one X1 box with XR15v2 remote. Tried to replace second old DVR box with new X1 box and XR15v2 remote. Box stuck on Select Your Language screen, won't respond to remote.

A+D+981 no response.

Xfinity + i TV says No Input.

Unplug & plug in no response.

Completely different X1 & XR15v2 (plan to have three total, as before) no response.