Your resource rooms have been working for as long as you remember. Why then, suddenly, do Resources in Exchange Don’t Respond to Meeting Requests? You set up these rooms ages ago and they just worked.  It is supposed to be easy.

You didn’t change anything. And the wild goose chase begins……Of the things it could be I will go through two fixes that didn’t work and one that did for me. 

Corrupt Free/Busy Data on Resource or Client Email Box 

This could be a reason Resources in Exchange Don’t Respond to Meeting Requests and was suggested to me by Microsoft. It is a program called MFCMapi. It is like a registry editor for your Outlook profile. From here you can open the resource room profile (You will probably need to create one) and locate two free / busy files. They are called localFreeBusy and Sniffer. You need to delete them. The screenshots are below: 

Basic Configuration Settings on Resource Not Correct 

Once again, nothing has changed so why would I check this (I am looking at you Microsoft)? They suggested the following: 

1. Check Room Mailbox Auto-Processing Settings 
Run this in Exchange Online PowerShell: 

powershell 
Get-CalendarProcessing -Identity “RoomName” | fl AutomateProcessing,BookingWindowInDays,AllowConflicts,AllBookInPolicy,AllRequestInPolicy,AllRequestOutOfPolicy,BookInPolicy,RequestInPolicy,RequestOutOfPolicy 

You want to see: 
– AutomateProcessing : AutoAccept 
– AllBookInPolicy : True (or the user should be listed in BookInPolicy) 

If not, set it like this: 

powershell 
Set-CalendarProcessing -Identity “RoomName” -AutomateProcessing AutoAccept -AllBookInPolicy $true 
 

2. Check Delegate Permissions 
Ensure the delegate has Editor or Full Access to the user’s calendar, and that the room is being added as a required attendee. 

Also, verify that the delegate is not using “Send As” or “Send on Behalf” in a way that bypasses room booking policies. 

3. Test Direct Booking 
Try having the delegate book the room directly (not on behalf of someone else). If it works, the issue is likely with how delegate bookings are processed. 
 
4. Use Message Tracking Logs 
If you’re an admin, run a message trace in the Exchange Admin Center to see if the room received the booking request at all. The messages were getting to the resource but the resource was not responding. It was stuck…. 

Advanced Configuration Settings on Resource Not Correct 

Here is how it finally got Resources in Exchange Don’t Respond to Meeting Requests fixed. 

At this point, it looked like a client-side issue. But Resources in Exchange Don’t Respond to Meeting Requests still! However, it was working on some users and not others. I was one of the affected users. Something changed and not by me or my colleagues…. 

Finally, I found this Article. It is an obscure article from about 4 years ago. The affected admin was having problems booking resource rooms and they were not auto accepting. It was different in that instead of allowing anyone to book a room, they were using delegates. However, the base issue was the same. 

If you run “Get-CalendarProcessing <resource room name> | fl” you get all configuration settings. There are 46 of them in total. Near the bottom, there is a setting called “ProcessExternalMeetingMessages”. It was set to false. It needs to be set to True: 

Set-CalendarProcessing <resource room name>   -ProcessExternalMeetingMessages $True 

Low and behold the message loop between the person / delegate booking a resource and the resource accepting were finally closed. Things started flowing again. 

How do you know you have Resources in Exchange Don’t Respond to Meeting Requests 

When this issue is evident users might complain of meeting reservations not showing up in room calendars, or worse, if it is an intermittent problem (in my case), users complain of double bookings. Basically, a user booked a room, and it was not marked off in the resource, therefore technically still available. A user who wasn’t exhibiting the issue would book the same time and it would reserve the room, hence the double booking! Frustrating the say the least. 

Why am I Telling You This 

It is important to know that what it takes to solve a seemingly simple problem can take a long time. For me it was reaching out to Microsoft several times. They were no help, but I didn’t give up on my relentless google search, trying to find the right phrase that would yield a result. You know how when you search for something on Google and a million search results come up? I only had about 2 dozen and the article that finally fixed my issue WAS THE LAST ONE. 

I wrote an article about my experience with Microsoft Support. I have had a lot of them. 

I am also going to open this post up to comments. Please let me know what your experiences have been. I would love to hear! 

Dan

I am an IT professional with over twenty five years experience in the field. I have supported thousands of users over the years. The organizations I have worked for range in size from one person to hundreds of people. I have performed support from Help Desk, Network / Cloud Administration, Network Support, Application Support, Implementation and Security.