You may face the “Some Addresses Can’t be Used Due to the Configuration for Specific Countries” error while generating an order on the Magento website, this error tells that the country you have added in the address does not allow by this website, you must have to enter the country or address which is allowed by this website.
To solve this issue just make sure that the country you have added in the address is selected in “Allow Countries” filed at Magento 2 admin. If not then select that country to “Allow Countries” or remove that country from your address.
Generally, if the country is not selected in the “Allow Countries” then you can not select that country in your address either at the front-end or at the back-end but in some situations if that country is selected at the time of testing and you have added this in your address and then you remove that countries later from the Allow Countries at that time this issue may occur.