Most frequent issue #1 : The app extension is not enabled. Please check this blog post to fix this issue.
Most frequent issue #2 : You are looking at your product page while editing your theme. Cowlendar does not always work on your theme editor. Please check your product on the live theme instead of looking at it in the editor.
Most frequent issue #3 : You have no inventory on your product. Please make to add some inventory or simply uncheck the "track quantity" field on your product page. Please check this blog post to fix this issue.
→ Make Sure To Have Some InventoryMost frequent issue #4 : Your product is not published on your Online Channel. Please check this blog post to fix this issue.
→ Make Sure Your Product Is Published In Your Online StoreMost frequent issue #5 : Your product is draft instead of being live. Please click the link to learn how to fix this.
→ Make Sure Your Product Is Published In Your Online StoreMost frequent issue #6 : You don't have an Add to cart button on your product page. Cowlendar _needs_ an add to cart button work. Please click the link to learn how to fix this.
→ How Do I Show The Add To Cart Button And Book Now Button