Can't open xfinity channels get error message

When I toggle down to the xfinity icon on my Roku TV and click on it no longer opens to the channels. I tried repairing the remote and that doesn't correct the problem. I unplugged the DVR and that didn't correct the problem. All the connections seem fine and everything else works. Not sure what to do next?What I get is an error message with instructions saying get closer to the TV or try repairing the remote. Can the signal to my DVR be checked remotely to see if the signal is good?