Two offers that each work alone frequently do nothing together.
Shopify distinguishes product, order and shipping discounts, and combination rules are set per discount rather than globally.
Two product discounts generally do not stack, which surprises merchants who built each offer separately weeks apart.
The failure is silent — the discount simply does not apply, no error is raised, and the shopper sees a total that does not match your landing page.
Automatic discounts and discount codes behave differently at accelerated checkouts, and codes can be structurally unenterable.
The usual causes, in order of frequency: a combination setting preventing it from applying alongside an active automatic discount, a date range not yet started or already ended,
The full guide has the formats, the deadlines and the worked examples.