To confirm, are you testing your Shopify Payments gateway? If so, you’ll want to make sure that this is the document you’re using for guidance, rather than this general testing order one.
Can you also double check if your test order is more than $1 USD in amount? As the system will present you with an error if your test purchase is lower than the equivalent of $1 USD in any currency.
To further troubleshoot this, you can also follow the steps below:
Try to complete a test order on your store via an incognito window
Or, you can use your usual browser but to clear the browser’s cookies and cache
You can also try another browser. For example, if you’re using Safari, you can try to complete your test order on Chrome or Firefox
You can also try to use another device, if available
If you’re still having issues with this after following the steps above however, you can contact our Live Support team so that we can investigate the errors in more detail from our end. To get in touch with our team, you’ll need to login to your store via the Help Center here, or via this link if you have a Shopify Partners account. Once logged in, select a topic that best fits your query or situation. From there, you’ll 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.
It’s great to see that you’re conducting some tests on the checkout page — this will allow you to understand the checkout process better, and implement the best checkout strategy on clients’ stores. If you need some ideas on how to further optimize this aspect of a store, feel free to take a look at our resources below:
Thanks for getting back to me with those screenshots, they’re super helpful! I can now see that a whole string of numbers has been entered under the Card number heading, which is most likely why an error message is presented.
As seen on the table below, you’ll need to instead enter one of the numbers to simulate a transaction.