I've set my default country (Spain) in admin, also set it to be the only destination country available for shipping, however in the cart the default country is United States. How can I change it?
General -> Country Options -> Allow Countries was bugged until 2.1.
Instead to have a default country (Spain) in cart shipping quotes you have to set it in
Tax -> Default Tax Destination Calculation -> Default Country.
I continue to don't understand what
General -> Country Options -> Default Country means if it is near to
Allow Countries that is referrred to shipping quotes.
It is struggled.
In the admin got to
Store -> Configuration -> General -> General
In there you can set the default country and the allowed country.