Xfinity Will No Longer Play Though HDMI Splitter

I have an Xfinity RGN200N cable box. For years I have used it through an HDMI splitter to my older Samsung tv. I also have DISH (for international TV) and a D Link streaming box for Netflix. Now, only DISH and the D Link box will play through the splitter. The Xfinity cable has no signal through the HDMI splitter. The only way I can watch Xfinity is to unplug the splitter and hook the Xfinity straight into the HDMI on the TV. Any suggestions on how to fix the problem?