URL of some products could not be reached. Review domain settings and product URLs

Receiving the above error when trying to process a test transaction.

Running a Next.js local dev environment at localhost:3000. Have followed documentation here: Order validation – Snipcart Documentation regarding setting the data-item-url and setting default domains. Current default domain settings are protocol: http and domain: localhost:300.

Have tried both relative and absolute URL paths for the add to cart button, like so:

<button className={`${s['single-product__btn']} btn snipcart-add-item`}
                  // data-item-url={`http://localhost:3000/products/${props.slug}`}
                >Add to cart</button>

One is commented out, but essentially they both translate to: http://localhost:3000/products/my-product, which is the same URL the item being added to cart lives.

Any other thoughts? Thank you

The crawler cannot access localhost, due to being on a server. You may either test on a test server it can access or use the JSON crawler, with the JSON being on a server it can access.