Select a country:territory from the list of valid countries Salesforce Exception

"System.DmlException: Update failed. First exception on row 0 with id 0018c000026ZmPmAAK; first error: FIELD_INTEGRITY_EXCEPTION, There's a problem with this country, even though it may appear correct. Please select a country/territory from the list of valid countries.: [BillingCountry]" exception occurs when the Country value used is not present in "Configure States, Countries, and Territories". Blog Post: https://www.infallibletechie.com/2022/09/salesforce-fieldintegrityexception-theres-a-problem-with-this-country-even-though-it-may-appear-correct-please-select-a-country-territory-from-the-list-of-valid-countries-billingcountry-exc.html