Invalid address: (addAnAddress to): Enter your email address here

Hi,

We'll need more information to be able to help.
Could you provide a link to the shop and precise instructions to reproduce the problem so that we can analyse the situation ?

Hi,

That error doesn't come from the checkout.
After you're redirected to the checkout, if you press enter after selecting the URL in the address bar of your browser (so that it redisplays the current page), you won't have that error.
Also, there is no such error message in HikaShop.
And also, on the page before the checkout, that is not a HikaShop product page but some kind of form from another extension. I believe that the error comes from that extension. The error message is only displayed on the HikaShop checkout because that extension redirects you there after you submit the form.