Good day everyone, may I know how to use add mask and slide with collection list?
you won't be able to put a collection list inside of a slider component like that. That is why you are running into errors.
With the Finsweet CMS Slider - the slider component and the collection list become two separate objects within your project and the custom code that powers the Finsweet CMS Slider picks up your CMS content and inserts it into the slider using javascript.
https://finsweet.com/attributes/cms-slider
You'll want to check it out.
If you run into any other issues, be sure to run your project through their automated support.
After that, if you have any other questions - be sure to include your read-only link and published URL and I'll be happy to take a look.