Exported video file missing after export?

Hi,

I'm not sure if this has already been asked (partially because I don't know exactly what to search for), but I'm having a weird issue: I have a simple project in PP that is just 2 .mov files stuck together and rendered out as a .mp4 with the settings in the attached screenshot.

The problem is that the file shows up as a 24kb file with no video length and I can't open it. I've exported twice with the exact same settings and gotten the same result twice - what am I missing here? I'm currently using Media Encoder to see if that will produce a different result (with the exact same render settings), but I'm legit lost.

Thanks!

[Moderator note: please add images directly into your post rather than linking to them, which requires users to download unknown files to their computer.]