"Uncaught TypeError: AdobeAn.getComposition is not a function"

I have an Animate canvas that I made a few years ago for a client, and it worked fine. Recently it had to be updated - just a few graphics altered, no major rewrite of code or anything. Now, it won't load and I get the error message "Uncaught TypeError: AdobeAn.getComposition is not a function".

It just sticks on the preload screen.

The site has Cloudflare, if I disable Cloudflare by turning on its development mode, the canvas starts working again and the error no longer appears.

Obviously I can't leave Cloudflare turned off - what do I need to do to get round this problem?

Thanks