Lottie export for the web doesn't work with Advanced Outline

I get errors while exporting.

Here is the file,
notification.sifz (47.8 KB)

I installed the lxml, and I created an Advanced Outline in a new file and just tried to export it, it didn’t give any errors. But when I tried to export my previous animation, which is

It gave me errors.

(I cannot select the text so I put the screenshot, also I can’t scroll down to see what the error actually says)