Had a hard time parsing the title for some reason. So what happens is that the people validating apps for the store look for parts of the application where the user has to select their country. If they find that Taiwan is listed as a separate country instead of a region of China, they refuse the app.
The usual workaround is to label the dropdown "country or region" so that everyone can apply their own interpretation of what counts as a country and what's just a region.