Adobe Animate plugin - Frame by frame animation exports/previews as blank screen

I’ve been trying out the Adobe Animate Lottiefiles extension, and haven’t been able to get it to export or preview properly. I created a frame by frame animation using the pen tool, and the preview appears blank after rendering. There are no nested symbols, or any symbols at all. Is there something I am doing wrong?

The dimensions are 842x250
Operating system: Win10
Software: Adobe Animate CC v23.0

What animation technique did you use? Adobe Animate is very picky about what can be exported to lottie. Could this be done in After Effects instead?