I have a friend who went through a few different HDMI splitter devices. They are not all made the same. He finally ended up with a Gefen, which was more expensive but it ended up working the best. The other splitters had signal problems as well as compatibility problems.
https://www.bhphotovideo.com/c/product/1202411-REG/gefen_gtb_hd4k2k_142c_blk_1_x_2_hdmi.html/?ap=y&a...
The Gefen 1:2 HDMI splitter above is a lot more expensive, but it works. The BHPhoto seems to have one of the better prices on this item.
https://www.bhphotovideo.com/c/product/1202411-REG/gefen_gtb_hd4k2k_142c_blk_1_x_2_hdmi.html/?ap=y&a...
The Gefen 1:2 HDMI splitter above is a lot more expensive, but it works. The BHPhoto seems to have one of the better prices on this item.