When trying to redeem my 14-day Gold trial included with the Xbox One (S) console I receive this error (I've tried the website microsoft.com//redeem
You can’t acquire this item in your currently selected language. Change your language region in Settings or go to microsoft.com//redeem.
The console has been purchased from a leading retailer in the country I reside in and "location" in the Xbox system setting matches as well, but "language" and "language region" have been set to English. I'm wary of changing the setting since account funds don't move between regions and Microsoft doesn't directly tell which of the three settings (language, language region, location) you have to modify:
How to change your country/region on Xbox One
Sign in to your Xbox One console.
Press the Xbox button to open the guide.
Select Language & location.
Select your new location from the list, and then select Restart now.