I changed the country setting to mainland China to download an app and want to switch back to US. After filling out all the information including payment methods and phone number, it keeps saying "we've run into a problem. please try again" and succeed.
iPhone SE, iOS 13
Change your Apple ID country or region - Apple Support
The above info may or may not help, usually changing country/region is when you move to another country and not just for downloading an app then switching back and there is a process to follow before switching which is explained in the above so this is why you have an issue.
If you can't complete any of the steps, can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support.
Change your Apple ID country or region - Apple Support
The above info may or may not help, usually changing country/region is when you move to another country and not just for downloading an app then switching back and there is a process to follow before switching which is explained in the above so this is why you have an issue.
If you can't complete any of the steps, can't change your country or region, or you have less store credit than the cost of a single item, contact Apple Support.
Run into problem when trying to change country/region in app store
