Resolve 16 - Audio is not rendering/exporting after delivery

So, this has happened multiple times now to where, once I have finished editing my video and go to render/export it, when it is finally done, the finished clip on my computer has no audio. There is audio WITHIN DaVinci, both while I am working on it AND in the Deliver tab, but the finished product after exporting has no audio. The last time I tried it three times before I magically had audio. This time I am on the third render because the first two had nothing. I've done a search but everything that comes up addresses something I've already done to fix it. For example, here are the settings:

1920x1080 HD
Frame rate: 29.97
Format: MP4
Codec: H.264
Audio: Main 1 (stereo)
Audio Codec: AAC

Please help, as I can't figure out why it's doing this sporadically.

[Peter Chamberlain]

Did you select a pre configured render option from the top of the render settings?
Is 'render audio' turn on?
Are the track enabled in the audio page?

I picked the pre-render YouTube and then changed the settings to what I said in the initial post.

Yes to both of the other questions. After this had happened twice, I'm double checking everything. Weirdly, on both projects the THIRD time I rendered them, I had sound.

How are you testing the audio of the exports?

I'm playing the file once it's exported.

Same problem with audio. I have a project with two audio tracks. Interestingly, exported MP4 plays ONLY one track in VLC player while ONLY another track in Windows media player.

[Peter Chamberlain]

can you make as small project with one clip that repos this, export the drp after the render and the rendered clip and we will look.

even i had the same issue after exporting no audio. i tried some settings but that time it got exported with 5.1 and even took time "2 hours" to export a 30 min alexa mini footage.My question is what is the correct settings to export with audio or if dabinci resolve can make that as a default option it will be great- any final out we need with audio.