For compatibility with the Try Before You Buy APIs that TryNow uses, Shopify mandates the presence of a draft checkout in the Checkout Extensibility environment. Thankfully, setting this up is straightforward and doesn't require launching a new checkout. You simply need an unpublished draft.
Steps to Create a Draft Checkout:
Navigate to your Shopify admin.
Select Settings > Checkout.
In the Checkout customization section, click Create draft checkout. Remember not to publish it.
