Hi @Emma Svensson,
Welcome to our MS Q&A forum!
Regarding your problem, have you checked in OWA to see if you can see the room list and rooms properly?
By research, I found a similar thread mentioned that it might be something in the backend which takes time to sync and populate the new resources in Outlook. I recommend waiting for a while, usually up to 24 hours, and then checking again to see if the room list appears in the room finder. You can refer to:
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