Project Audio Lost After Conversion to MP4

Hello! I’m using Captivate 2017. I’ve re-scaled a number of simple projects with audio included in the text captions from 1024×627 to 1920×1080. After doing so, the audio still plays when I view individual slides or run through the entire project in Preview mode, but when I attempt to publish it as a video, the audio included in the captions is lost. Any idea what might be going on?