Error when changing Region to Singapore for Minecraft purchase

[resonantscute]

I've tried to buy Minecraft for my friend, but every time we change the region from the USA to Singapore, an error occurs. We've attempted this on both Chrome and Edge, but nothing seems to work. I already have an account, but even when I try to buy it for him, the error still appears when the region is changed.

Can someone help us resolve this issue?

Thanks.