Add to cart Button not working

Shopify Discussion

Topic summary

  • Main issue: The Add to Cart action fails on all product pages with the error “required parameter missing or invalid items.” Theme in use: Lammer v4.0.0.

  • User request: A step-by-step solution to resolve the error.

  • Latest update: A responder asked for the store URL to investigate further. No fix or diagnosis provided yet.

  • Status: Unresolved and pending further details (store URL). Key cause not identified from the discussion so far.

Summarized with AI on December 21. AI used: gpt-5.
1

Hello, Shopify Team

In my store when I am going to add to cart it’s showing “required parameter missing or invalid items” in my all product pages. The theme name is “Lammer Version 4.0.0”

Can anyone please give me the solution step by step?

1 Like
2

Hi @sjamannitu , can you share your store url?