I have had no issues for the past 5 years until this week. When clicking Add to Cart, customers are getting an error stating Parameters Invalid…
Can someone please assist me with figuring out this issue!! Thank you
Topic summary
A Shopify store owner is experiencing intermittent “Parameters Missing or Invalid” errors when customers click Add to Cart on certain products. The issue began after updating to the new Canopy theme a few weeks ago.
Key Details:
- Error message: “Required parameter missing or invalid: items”
- Only affects some products, not all
- When customers click “More Payment Options,” the item appears in cart correctly
- Store has been running without issues for 5 years prior
Root Cause Identified:
The error occurs when users click Add to Cart before the product form JavaScript fully loads, causing the form to submit natively before it’s ready. This is more likely on slower connections or when visiting product pages for the first time.
Proposed Solution:
Disable the Add to Cart button by default and enable it only after the JavaScript loads. This requires modifying the product section template and product-form.js file. The store owner plans to contact theme developers first, as code modifications may complicate future theme updates.
Status: Issue diagnosed; awaiting response from theme developers.
You need to share your store URL to get any kind of meaningful help.
Any other info about when it happens will help too.
Thanks Tim. I was so frustrated in the moment that I neglected to provide any additional info. The website is www.woolandwaves.com
The error does not happen with all products which makes it hard to pinpoint where the issue is. This is one of the products where the error code happens when a customer selects Add to Cart - https://woolandwaves.com/products/peace-fleece-worsted
I updated to the new Canopy theme a couple of weeks ago and that is when the issues started. I can usually figure these things out but this one has me stumped and very frustrated (and losing revenue).
Any help is greatly appreciated!
Christine
hmm. unable to replicate (multiple browsers, multiple devices) – maybe it was a temporary glitch?
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Hi Tim,
I thought it was fixed as well and then this morning a customer messaged indicating they were seeing the error code when attempting to Add to Cart this product - https://woolandwaves.com/collections/laxtons-by-laxtons/products/laxtons-sheepsoft-dk
It is the same error message as before - Parameter Missing or Invalid: Required parameter missing or invalid: items
If the customer clicks on More Payment Options it takes them to the checkout page where the item is showing in the cart.
It is not happening on all product pages, just some.
Ok, I was kinda able to replicate.
Not sure if this is the same problem though 
For this I had to slow down my connection and then it happens like this – I clear cache, go to a product page I have not visited before and click ATC button immediately.
The result is
This happens because JS code for the product form is not yet loaded when I click ATC and the form is submitted “natively”, but it is not ready at this moment.
Again, not sure if this is the same problem – you may ask your visitors whether the site/connection was slow when they’ve encountered the problem.
To mitigate this problem I’d disable the ATC button by default and enable it as part of the product form JS. This way it would be impossible to click the button until JS is ready.
The code change is not complex, but editing theme code will prevent (make more difficult) further theme updates, therefore I’d recommend contacting theme developers first – they may easily implement this and include in a theme update.
If the theme is already modified, I can help with this, but can’t give specific instructions without seeing theme code.
Roughly, need to find code like this in product section:
and add disabled attribute to the button:
Then, in assets/product-form.js find this line
this.submitBtn = this.querySelector('[name="add"]'),
and replace with
this.submitBtn = this.querySelector('[name="add"]'), this.submitBtn.disabled = false,
1 Like
Hi Tim,
Yes - that is the error page that pops up.
Your reply and modification suggestions are very helpful and I am going to to pass on this info to the theme developers and see what they say. I will get back to you if I need further assistance!!
I appreciate you taking the time to offer potential solutions.
Christine