After updating to 3.9.0 and Qt6, the country of my server changed without any changes to the config, apparently it is using Qt6 Country IDs now. I fixed it by updating to the new code in this list: https://doc.qt.io/qt-6/qlocale.html#Country-enum

Originally posted by @acerix in #2362 (comment)

If confirmed, this affects servers using our official releases on Mac and custom-built servers on other platforms (e.g. Linux with self-built binaries or distros which have switched to Qt6 such as Arch).