Mp4 export perfect but wont show in mp4 players or previews

[OTGxSylveon27887772zuf3]

So when i export my videos in 4k or UHD 
Optical Flow
Profile High
CBR - 100
on H267
it will export with no errors at all but some wont show in mp4 players or in previews some will but recently been having trouble with it some vids will only play audio but no video sometimes any reason why, and how i can fix it. And yes i did try to reinstall premiere pro 

[Ann Bens]

Which format is used (H267??) and why is Optical Flow checked.

Post screenshot complete export settings.

[OTGxSylveon27887772zuf3]

Sorry i thought the codec was 267 but heres the format

my bad

[MarekMularczyk]

Can you explain a bit more? I've never heard of H.267 codec. As far as I'm aware the latest one (which is new) is H.266...

Also, if using any new codec, Media Player won't play it, it;s a very old player. Try Films & TV or some good players like MPlayer or VLC player.

[OTGxSylveon27887772zuf3]

my bad on the format i thought it was 267 

but the way i used to export would be in 4k which the problem i think i would have would be like for software wise where after the export the video will have to get all of its frames and i would have to wait till its fully done kinda like a download after a update.

[MarekMularczyk]

4K shouldn't be a problem. It's not a matter of resolution, and H.264 is supposed to play on anything. I wouldn't use old Media Player ;-).  but Films&TV which comes with Windows will play it.