Some accounts don't seem to exist despite correct privacy settings.

I've had a working project for several months now where all of a user's trophy list is imported in detail. This has, and still does, work seamlessly for most users. However, I've recently had a user report that their account doesn't link - I have thoroughly explored this and everything about the account on PSN is correct; privacy is fully public etc.

The username is 'Maerlyn1999' and this is a direct link to their profile on PlayStation: https://profile.playstation.com/Maerlyn1999.

Does anyone understand why some accounts aren't found by the API & what's causing this?