In webmail, the calendar shows available rooms, but on the outlook client they don't or contradicts webmail. Primary email has full access permission in EAC to all the rooms.
-The web version shows available rooms and the client doesn’t. It is strange since at some hours the available room and others it doesn’t so we tried changing the active hours of the rooms to 7am to 7pm but that made no difference. Although it says no syncing errors it doesn’t seem to sync this data correctly.
-I created an new account on the office 365 site and loaded that onto outlook on a separate laptop, then opened a webmail version on my computer and also had my own account running on my computer. So I had the calendar planning open on 3 instances. The new account was on some hours slightly different with my account but mainly the same and the web version had some differences with the two running on the outlook client. The web version was consistent with availability of the rooms, the new account was slightly more in sync. So this must be a sync problem with clients.
Please see if you are using the latest version of the semi-annual channel of Office. Under your outlook, please see if you can take yourself out of cached mode by doing File > Account Settings > Account Settings > Double click on your email and un-check 'cached mode' > restart Outlook.
Check to see if that resolves your issue. Online mode is exactly like web version, you get the most up-to-date data from the server.