PayPal SandBox error using buy now button - paypal

Question

I have a page on my computer that has a simple buy now button with the following code:
<script src="paypal-button-minicart.min.js"></script>
<script src="paypal-button.min.js?merchant=8TYNWA5KGBSPE"
data-button="buynow"
data-name="My product"
data-amount="15.00"
></script>
<form action="https://www.sandbox.paypal.com/cgibin/webscr" method="post" target="_top">
<input type="hidden" name="cmd" value="_xclick">
<input type="hidden" name="business" value="8TYNWA5KGBSPE">
<input type="hidden" name="lc" value="GB">
<input type="hidden" name="item_name" value="Football lessons">
<input type="hidden" name="amount" value="15.00">
<input type="hidden" name="currency_code" value="GBP">
<input type="hidden" name="button_subtype" value="services">
<input type="hidden" name="no_note" value="0">
<input type="hidden" name="cn" value="Add special instructions to the seller:">
<input type="hidden" name="no_shipping" value="2">
<input type="hidden" name="bn" value="PP-BuyNowBF:btn_buynowCC_LG.gif:NonHosted">
<input type="image" src="https://www.paypalobjects.com/en_US/GB/i/btn/btn_buynowCC_LG.gif" border="0" name="submit" alt="PayPal � The safer, easier way to pay online.">
<img alt="" border="0" src="https://www.paypalobjects.com/en_GB/i/scr/pixel.gif" width="1" height="1">
</form>
But I get the error:
PayPal cannot process this transaction because of a problem with the seller's website
When I click on it, I'm logged in as a test user on the sandbox and I don't know what else to try. Why am I getting the 'cannot process this transaction' error?

Answer 1

To generate a non-hosted/clear text button follow these steps:
Log in your PayPal account www.paypal.com
Click the tab "Merchant Services" to access the Merchant Tools tab.
In the Website Payment Standard section select the type of button you would like to create (Buy Now, Add to Cart, Donation, Etc…).
Click "Create your button now" to access to the PayPal Button Factory.
Fill out the fields you will need in your button (Item name, Price, Currency…).
Click the tab "Step 2: Track inventory (optional)" then uncheck the box "Save button at PayPal".
Click on "Create Button".
The encrypted HTML code of your button will be displayed.
Click on the link "Remove code protection"
The HTML code of your button will be displayed, click "Select Code" and copy it to your website.
You can also find a helpful video here.