Thank you for getting in touch. Do you have Latvia added to any of your shipping zones or profiles? If a country is not added to your shipping settings and has no eligible rates set, then the customer will not see the country appear at checkout when they try to complete their purchase.
If this is the case and if you intend to ship to Latvia moving forward, then you can add the country to your shipping settings and add some rates that will be charged to customers ordering from there. You can then encourage the customer to attempt to complete their checkout again.
Please bear in mind that shipping products from the United States to Europe will typically come with a significant shipping cost, so you'll want to do your research on how much you can expect to pay to ship your products and add rates that reflect this. I'd recommend checking out our blog post on international shipping if you're only starting to sell your products across borders.
If you're not interested in selling to Latvia in the long run but would still like to allow this customer to buy from you, you can do so by creating a draft order that can then be sent to the customer. You'll want to ask the customer for their address first, and once you have that, you can find out how much it'll cost to ship the products to them and include a shipping charge as part of the order. Most couriers will offer a shipping calculator on their websites that'll provide you with a shipping quote ahead of time. Once the order has been created, you can email it to the customer and they'll be able to pay for the order before you ship the package.
I hope this helps but please let me know if you have further questions.
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