If you are seeing the Cannot find variant error when trying to add your bundle product to cart, please double check the following settings.
Is your bundle product Active?
Is your bundle product published to Online Store?
Are you viewing the changes on your live theme, or a preview theme?
Sometimes preview themes can be cached, or a little buggy. Try going to your product link directly:
For example, navigate directly to your product. The url should look similar to this:
https://biscuits-bundles-demo.myshopify.com/products/cupcake-12-pack
The link should not look like this:
https://56mzkn6a9z06fh4f-59994568057.shopifypreview.com/products_preview?preview_key=8d5f2207e5f80240da49956d7335e5a7
Next Steps
If the issue persists, please reach out to us and we'll assist.