Why is it asking for an ID number?

When a customer just tried ordering from our site and the checkout asked for an i.d. number. What is that and how do we fix it?

Thank you in advance. 
Dan

Hi. This is a validation that takes part in a payment module. Missing order id could indicate the LiteCart order id was not provided in a request to the service provider. Or the service provider's transaction reference was not provided. Either way, diving into the payment module code is what is needed.

Thanks Tim. It seems that it's only for some products. Other products work just fine.