Intermittent “Parameter Missing or Invalid errors” - WE NEED HELP! -$1,000 bounty to identify cause

Technical Q&A
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Topic summary

A Shopify store owner is experiencing intermittent “Parameter Missing or Invalid” errors when customers add products to cart on mobile devices (specifically replicated on iPhones). The issue occurs randomly—approximately 1 in 5 times when adding products with options.

Key Details:

  • The store uses an app that adds products as options
  • Errors only appear on mobile, not desktop
  • The current developer cannot replicate the issue and therefore cannot troubleshoot
  • Shopify support has attributed the problem to the developer
  • Business is suffering with declining conversion rates

Current Status:

  • Owner is offering a $1,000 bounty to identify the root cause
  • Two community members with relevant experience have responded and requested store details
  • Screenshots of the error messages have been shared
  • Discussion remains open as the owner connects with potential helpers via private message
Summarized with AI on October 28. AI used: claude-sonnet-4-5-20250929.
1

WE NEED HELP!!! Our developer can’t figure out the issue - and Shopify support blames the developer!

We recently launched an updated site, hired an experienced Shopify developer, but are having intermittent issues with add-to-cart errors - missing parameter and general errors.

We are using an app that adds products as options. In some instances, and randomly, we are receiving the below errors. The issues only occurs on mobile devices - it was replicated on two iPhones. There’s no consistency as to what causes it. Statistically, if adding 5 products with options to the cart, it will occur randomly, 1 out of 5 times.

My developer says he cannot replicate the issue and therefore he can’t troubleshoot. I need a fresh set of eyes on this as my business is suffering and conversion rate is down.

I’m attaching some screenshots. Please message me directly and I can provide the store name.

Thank you!

This error message could occur
This error message could occur1801×2063 49 KB

More frequency, this message will occur after adding to cart
More frequency, this message will occur after adding to cart1179×2132 41.5 KB

2

Hi @Work24X7

I would like to check out your issue, but could not send you direct message, can you try from your side or email me at laza@binaery.com

3

Hi @Work24X7

However, it seems your direct messaging is not enabled on the community, so I can’t send you a message.

Could you please send me a direct message with a product link? This will help me review the problem more effectively.

I’ve seen this kind of issue quite a few times before and have helped resolve similar cases.

Looking forward to hearing from you!

Best,
Felix

4

I sent you a private message.