Outlook Web – "Ghost" Categories in People (Contacts) That I Cannot Manage

Hello everyone,

In Outlook Web (Outlook on the web), under the People (Contacts) view, I see some categories that I cannot manage. These categories do not appear in the category settings list (where you can normally rename or delete them). They also have no contacts associated with them – I suspect they are leftovers from old contact imports.

Question: How can I remove these “ghost” (or “zombie”) categories from the Contacts view in Outlook Web?

Thanks in advance for any help!