Error: "Relative Asset Check" when validating for Google Ads

Hello,

 
I've animated a banner (HTML5 Canvas) with Animate CC for Google Ads. When validating the zip file I get the error below. What does this mean and how do I fix it? Please help, Obi-Wan Kenobi....

Relative asset check

You can only reference files found in your uploaded .ZIP file, and the file listed above is not found there. To continue, remove any references in your HTML file to assets found outside of the .ZIP file.

The asset listed in the error message cannot be found in your .ZIP file. You will also need to remove any references to that file. The only allowed external references are the following:

• Google Fonts
• Google-hosted jQuery