Add to cart intermittently fails across certain browsers/devices; upsell apps show a perpetual loading icon. Merchant updated the theme but the issue persists.
Support tested the store on two devices and browsers and successfully added items to cart (evidence provided via screenshot). The problem may be inconsistent or environment-specific.
Suggested troubleshooting:
Status: Unresolved; further data collection and testing are required, particularly ahead of BFCM (Black Friday Cyber Monday). Ancillary guidance on email marketing for BFCM was shared.
Note: A screenshot was central to demonstrating successful add-to-cart behavior during testing.
Hi
My add to cart buttons are not working.
For some browsers / devices it is working but i got a lot of customer complaints and its not working.
Updated my theme in the hope it would work… Still not working.
www.wildcameraxl.nl please please help!
Black friday coming up… Did so much work for this week 
Furthermore some upsell apps aswell, the loading icon keeps loading and no progress.
Hi, @Stijnmadou .
I’ve tested your store on my end on two different devices and browsers and was able to successfully add a product to cart, as seen below.
Have you gathered information from your customers, to see if there were any underlying trends between those that weren’t able to add items to cart? For example, were they all based in the same region? Are they all using the same browser too perhaps?
To troubleshoot this on your end, you can install a fresh copy of a Shopify theme by going to Online store > Themes > Explore free themes and select a theme to add to your library. From there, click on Actions > Preview, and you can then test your add to cart button to see if it’ll allow you to successfully add a product to cart.
If the issues don’t persist on the fresh Shopify theme, a third-party app on your store may be interfering with how the add to cart button is meant to function. If you or a developer working on your store have made any code changes recently to your theme, the newly added code may also be the cause of this issue.
If you need further help to look into this, you can contact our team so that we can take a closer look at your account from our end. We aren’t able to do this via the Community Forums at this stage, due to security reasons, but you can reach out to our Live Support team via our Help Center here. Once logged in, select a topic that best fits your query or situation. You’ll then be taken to a page with a list of relevant support articles, and you can scroll to the bottom of that page to select your preferred contact method with our team. From there, our Live Support team will be able to securely access your account and investigate your store in more detail.
Can you also confirm which theme you’re using for your store? It looks like it could be the Debutify theme, is that correct? If this is the case, or if you’re using any other third-party theme on your store, just a note that you may also need to contact the theme’s Support team directly to further assist you with this matter. As third-party themes are developed outside of Shopify, our scope of support is rather limited, so the theme’s Support team would be best equipped to troubleshoot in more detail. But do get in touch with our Live Support team to begin with, so that we can help perform some more initial troubleshooting on your store.
Apart from this issue, how is your Black Friday Cyber Monday (BFCM) preparation going? I see that you have products on your store that are on sale — if you’re offering incentives for your customers, remember to also notify them of this sale that you’re currently offering! Email marketing is a great way to help you spread the word of your sale, and if you need some tips and tricks for crafting your email campaigns we have a couple of great blogs you can look into, feel free to have a read of them below:
