Xfinity Will No Longer Play Though HDMI Splitter

I'd probably suggest swapping it out with a newer box as that one isn't an X1. The best way to do so is to pop by a retail store. Not sure if it has anything to do with HDCP as I'm not an expert, but I highly doubt it unless you changed TVs recently as well.

It seems like Comcast has done something to the Xfinity boxes such that splitters no longer work. After an old box failed they sent me a new one. The splitter worked on the old one but not on the new one. 

I have a new splitter which I haven't tried yet.

Will post here if it solves the problem.

Problem solved.

I bought a new splitter from Bombay electronics.  I don't know what the model number is but it's called 

Orei 1x2 2.0 HDMI Splitter 2 Ports with Full Ultra HDCP 2.2, 4K at 60Hz & 3D Supports EDID Control - UHD-102

I'm haveing the exact same problem. I have gone through 2 new spitters and neither one worked. I have another new one now and it still doesn't work. The new splitter is from Best Buy and in their brand Rockfish. Any ideas?

The problem is, I can watch one or the other not both. On the other one, both newer Sony's, it switches the input.

The following splitter worked for me:

Orei 1x2 2.0 HDMI Splitter 2 Ports with Full Ultra HDCP 2.2, 4K at 60Hz & 3D Supports EDID Control - UHD-102

I got the OREI UHD-PRO102 from Amazon and it works on new Comcast/Xfinity cable box.

Background: It depends on the whether or not your box supports HDCP and if it does, which version. Older boxes did not use or support HDCP so there were no issues using a splitter. Maybe 4 to 8 years ago Comcast implemented boxes using HDCP version 1.4, so a splitter that supports HDCP 1.4 was required. I used a $12, HDCP 1.4 compliant splitter from Amazon for a while until the cable box failed and was replaced by Comcast in December 2020. That splitter did not work on the new box. I purchased the OREI UHD-PRO102, which supports HDCP up to version 2.2 and it is working fine with the newest cable box received from Comcast. Per ROKU web site, HDCP 2.2 is needed to support 4K UHD resolutions (1.4 maxes out at 1080p). So if you get a new cable box (or DVD, ROKU, FireStick, etc) that supports 4K UHD resolution you'll need an HDCP 2.2 compliant splitter.