In order to use our standard shopping cart display that appears as an overlay "inside" your own Web page, you need to have at least one complete block of View Cart button code on every page that has any number of Add to Cart buttons. You don't need a View Cart button for every single Add to Cart button; just one View Cart per page will do fine.
This can also happen if you have pasted our code incorrectly, like breaking a single line of code into a multiple lines while pasting it, or sometimes Web page design software can modify HTML after you paste it in, which may sometimes garble an important part of our code. You might want to View Source on your page and find the button code there to compare to the original button code issued in your Seller Admin.
Broken/improper HTML in your page can cause problems, or if the way you place our button code does not nest tags properly -- e.g., if you have a
<form ...> tag without a closing
</form> tag before our button code, or if you open a tag like
<p> before our code and close it with
</p> in the middle of our code.
Adding some types of custom HTML mingled within our code can sometimes cause a problem, in which case you may want to start with our code as-given and then re-add your custom HTML bit by bit until you find what broke the cart -- e.g., you can put the code for a complete HTML table inside our code, or our code can sit within a single cell of a larger table, but you cannot split our code across different cells of a larger table that starts or ends outside our code.
In some rare cases, CSS in your page can also interfere with cart buttons and the cart (especially CSS declarations applied generically to DIV, BODY, etc.), and giving any element a
name="body" attribute can cause a problem as well.