Thank you for the screenshot showing the error message your customers are seeing at the checkout. This can happen for a variety of reasons and can take a bit of time to track down the issue. I provided some steps to troubleshoot error messages like this in a similar thread that I will link to here. And I will include the areas to double-check as well.
Make sure you do have shipping rates setup for the country/location of the shipping address you are testing. You can find your shipping rates under Settings > Shipping in your admin.
Check that all shipping locations are enabled (can be found on the bottom of the shipping rates page), this includes dropshipping services as well as physical locations.
Make sure your products are not marked as "no shipping required" in their product details. You can quickly double check this by using theBulk Editor.
Also in the Bulk Editor, check to make sure that your item weights are correct. It is common to see weights that are supposed to be grams be in kilograms instead, making it ineligible for the available shipping.
Make sure you have a default package setup to calculate your shipping rates with.
If you have more than one shipping profile, make sure that they have matching shipping rates so that customers can check out with all their items at the same time.
If you are still not able to find the issue please don't hesitate to reach out to our live support for additional help with this.To contact our live support please follow this link: Shopify Help Center - Contact Support, sign into your store account, search for your issue and use the contact support button at the bottom of the search results to see all our live support options.
Once you get this resolved please feel free to update the thread with the issue so that other merchants might be able to resolve similar errors faster in the future. Thank you!
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