Candy Rack discounts can be combined with other discounts. However, based on Shopify's limitations, it's only possible to achieve specific combinations:
order discounts with free shipping discounts
product discounts with free shipping discounts
product discounts with other product discounts
product discounts with order discounts (only available to eligible merchants)
order discounts with other order discounts
More information about combining discounts is available in Shopify documentation.
Candy Rack discounts should be automatically stackable with other discounts. If you experience any issues with that, check the discount coupon and ensure that the combinations are enabled. Just go to Discounts –> search for the respective discount coupons, and you should see if the Combinations are enabled for the discount coupon:
Do you have any questions about this? Feel free to contact our team via in-app chat or email at support@digismoothie.com.
Happy upselling,
Your Digismoothie team