Basket checkout event handler error

[LeoCopatti]

I downloaded the project and was trying to test the code, but when I checkout an order, it publishes on the RabbitMQ queue an erro named basket-checkout-event-handler_error, this error contains the following message:

String or binary data would be truncated in table 'OrderDb.dbo.Orders', column 'BillingAddress_ZipCode'. Truncated value: '11111'.
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_OrderItems_Orders_OrderId". The conflict occurred in database "OrderDb", table "dbo.Orders", column 'Id'.
The statement has been terminated.
The statement has been terminated.

What am I doing wrong here?