My Belgian customer has a nopCommerce 4.50.4 webshop.
She has many different shipment options for Belgium.
When nopCommerce tries to do /estimateshipping , or when it does /Checkout/OpcSaveBilling it inserts a database row into the GenericAttribute table.
This value has a limit of 4000 characters ( nvarchar(4000) ) in the database.
However, the value being inserted is XML and contains all shipping options for a given country (Belgium in this case), but also contains more info like the full description of every option.
Which, in the case of my customer results in a 4700 character string.
Insert fails because the value is too long, and checkout resets to the shopping basket screen... which means Belgian customers can no longer checkout...