Cannot upgrade iCloud storage on Windows

Hello, I have been trying to upgrade the storage of iCloud on the Windows app but when I press "Buy" I get an error 403 with a message that I do not have rights to access this webpage.

I have tried it on two computers, one with Windows 11 and one with Windows 10, both having the latest version of the iCloud app, and got the same issue. Also to note, I currently do not have access to an Apple device.

Thanks in advance.