Office 365 Users Not able to view Free/Busy and Room information of On-Premises

The other day I had to validate and solve a problem with calendar synchronizations between Office 365 and Exchange 2010 (and vice verse). I was aware that On-Premises users could see the status of all users calendars, but Office 365 users only could see the Office 365 users status. (Office 365 users were not able to view F/B information of On- Premises user mailboxes).

This scenario is valid for Exchange 2010/2013 and Office 365 hybrid architectures with or without ADFS. The errors that I had were this:

Trying to share a Calender between On-Prem and an Office 365 User:

"One or more users cannot be added to the folder access list"

The outlook/webmail calendar had errors:

"No Information. No free/busy information could be retrieved"

"The recipient's server could not be contacted. Contact your administrator"

Let's see the necessary steps for the resolution.

As mentioned above, the errors I had were these:

I separated the Powershell settings between Office 365 and Exchange On-Premises. I marked in red the settings that you must change.






Open the Powershell Console

$UserCredential = Get-Credential

Type your Office 365 username and password with administrator privileges

$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection

Import-PSSession $Session

Get-OrganizationRelationship | Set-OrganizationRelationship -TargetApplicationUri server_dns_onprem.domain.com

Get-OrganizationRelationship | Set-OrganizationRelationship -TargetApplicationUri server_dns_onprem.domain.com -TargetSharingEpr https://server_dns_onprem.domain.com/ews/exchange.asmx 

Get-OrganizationRelationship

Enter your Office 365 to On-Premises identity from the last command:

Set-OrganizationRelationship -Identity "O365 to On-premises identity" -TargetAutodiscoverEpr https://autodiscover.domain.com/autodiscover/autodiscover.svc/WSSecurity 

Be sure to disconnect the remote PowerShell session when you're finished. If you close the Windows PowerShell window without disconnecting the session, you could use up all the remote PowerShell sessions available to you, and you'll need to wait for the sessions to expire. To disconnect the remote PowerShell session, run the following command.

Remove-PSSession $Session

Open the Powershell Console

$UserCredential = Get-Credential

Get-FederationTrust|Set-FederationTrust -RefreshMetadata

Get-WebServicesVirtualDirectory| Set-WebServicesVirtualDirectory -WSSecurityAuthentication $false

Get-WebServicesVirtualDirectory| Set-WebServicesVirtualDirectory -WSSecurityAuthentication $true

Get-AutodiscoverVirtualDirectory| Set-AutodiscoverVirtualDirectory -WSSecurityAuthentication $false

Get-AutodiscoverVirtualDirectory| Set-AutodiscoverVirtualDirectory -WSSecurityAuthentication $true  

Get-OrganizationRelationship

Enter your On-Premises to Office 365 identity from the last command:

Set-OrganizationRelationship -Identity "On-premises to O365 identity" -targetowaurl http://outlook.com/owa/domain.com

It's time to test the settings from users between O365 and On-Premises. Be careful that you can only view F/B information and give Full Access to users. In the next table I show you what you can do between O365 and On-Prem users (from the time of writing this post).