Shopify-block-subscriptions_app_block doesn't show up

Hi,

I’ve recently got an early access to the Shopify own Subscription app. I’ve setup Product with Selling Plans as instructed. Then I followed this instruction (https://help.shopify.com/en/manual/products/purchase-options/shopify-subscriptions/setup#display-subscriptions-on-your-online-store) to display the Subscription Purchase Option for the product in the Online Store, but it’s not working. After adding the Subscription widget block into the Product template and save, nothing was added to the page visually. I then published and reviewed the theme, the ‘purchase option’ block still didn’t show up either. I used the browser inspect tool, and found this

in the html, but nothing appeared visually.

Could you please help me with this? Thanks in advance.

Regards,
Thanh