Why am I getting a 500 error when trying to buy Add-Ons? Please double check your payment method on file by going to Account --> Edit Account Settings --> Billing. Then, try making your purchase again. Our engineers are looking into this. Related articles When do Add-Ons go live? Can I cancel my Add-Ons purchase? Why am I receiving an error when I try to choose my product? Who is eligible to buy Add-Ons? Are all products available for Add-Ons?