If you see the error "Internal Error" after activating your item, then most likely you have inserted an incorrect link.
Please make sure you only insert a link to your review page.
Go to the Items page and Select the item in which the error is present and click "Edit"
Make sure that the "Add a link to your reviews page" field does not contain anything other than a link to your page. For example, your company name.
If the field contains any text other than a link, delete it and click "Continue"