It's quite clear in the T&Cs
19 Points will be awarded for Qualifying Stays booked through IHG’s central reservation offices, IHG web sites, the IHG App, authorised travel agents (excluding online travel agents such as Expedia.com and Booking.com, and unauthorised agents on online vertical travel portals), or directly at the hotel.
The bolding and italics are as per the website not mine
https://www.ihg.com/content/gb/en/cu...care/member-tc