I'm rendering a project for a pro video house from 1080i, 29.97 to mp4 level 4.1 at various bitrates, from either Premiere or queuing to Media Encoder (same results).

Windows refuses to play the resulting files. VLC Media Player will, however. I've tested on three computers and three versions of Media Encoder. In the oldest version (2019), low bitrate files would play in Windows, but with two newer versions none do. So what's up?

I don't own copyright on this, but for 15 seconds let's call it "Fair Use."