I recently switched from AT&T UVerse to Comcast/Xfinity and received a new cable box (marked as Xfinity XG1-A and with a label Arris Group AX013 ANM) and a new remote (Xfinity XR11). I used the Slingplayer Desktop application to reconfigure my Slingbox 350. My new cable box is not listed under Comcast; I selected model X1. I made several attempts of resetting the Slingbox and going through the steps, all resulting in getting a P-1 error when I tried to view my Slingbox on the web. I even tried deleting the existing Slingbox and starting fresh. Same result. Any suggestions? Also, where is the best place to osition the Slingbox pyramid IR detector with this cable box?