On-premises Exchange Server calendar with Microsoft Teams

To seamlessly integrate calendars between your on-premises Exchange Server and Microsoft Teams in a hybrid environment, follow these steps.

Prerequisites

To successfully integrate on-premises Exchange calendars with Microsoft Teams, ensure the following are in place:

• Hybrid Environment: Your on-premises Exchange server and Office 365 are interconnected through a hybrid configuration.
• Directory Synchronization: Azure AD Connect maintains alignment between your on-premises Active Directory and Azure Active Directory.
• Hybrid Modern Authentication (HMA): Modern authentication protocols are supported through HMA.

Step-by-Step Integration

1. Configure OAuth Authentication

To allow Microsoft Teams to access the on-premises Exchange calendar, OAuth needs to be configured between Exchange Online and Exchange on-premises.

1. Configure OAuth between Exchange Online and Exchange On-Premises: Open the Exchange Management Shell on your on-premises Exchange server. Run the following commands to configure OAuth authentication:

PowerShell Script

$serviceDomain = "<Your Exchange Online Domain>"

$organizationDomain = "<Your On-Premises Domain>"

?# Configure Exchange Online as a partner application

New-PartnerApplication -Name "ExchangeOnline" -ApplicationId "00000002-0000-0ff1-ce00-000000000000" -Realm $serviceDomain -AppOnlyPermissions @("Calendars.Read ", "Calendars.ReadWrite")

?# Configure the on-premises Exchange server as a partner application

Set-PartnerApplication -Identity "ExchangeOnline" -ApplicationId "00000002-0000-0ff1-ce00-000000000000" -Realm $serviceDomain -AppOnlyPermissions @("Calendars.Read ", "Calendars.ReadWrite")

?# Configure the OAuth settings

Set-OrganizationConfig -OAuth2ClientProfileEnabled $true

?2. Verify and Enable Hybrid Modern Authentication

Ensure that Hybrid Modern Authentication is enabled for both Exchange Online and on-premises Exchange.

1.???? Enable Hybrid Modern Authentication in Exchange Online:

o?? Confirm that HMA is enabled for your tenant.

PowerShell Script

Get-OrganizationConfig | Format-List OAuth2ClientProfileEnabled

If it is not enabled, enable it:

Set-OrganizationConfig -OAuth2ClientProfileEnabled $true

Enable Hybrid Modern Authentication in Exchange On-Premises:

·?????? On the on-premises Exchange server, run the following command:

Set-OrganizationConfig -OAuth2ClientProfileEnabled $true

3. Configure Microsoft Teams to Use On-Premises Calendars

Microsoft Teams automatically integrates with the Exchange calendar, whether it is on-premises or online, if OAuth is configured correctly.

1. Check Calendar Access: Log in to Microsoft Teams with a user whose mailbox is on-premises. Check if the calendar tab is accessible and showing the correct information.
2. Troubleshoot Integration Issues: Ensure that users' UPNs match their primary SMTP addresses. Verify that the Autodiscover service is properly configured and reachable from the internet.

4. Configure Free/Busy Information Sharing

To enable free/busy information sharing between on-premises Exchange and Exchange Online, configure the Organization Relationship.

1. Configure Organization Relationship in Exchange On-Premises:

New-OrganizationRelationship -Name "O365 Relationship" -DomainNames "<Your Exchange Online Domain>" -FreeBusyAccessEnabled $true -FreeBusyAccessLevel LimitedDetails -TargetApplicationUri "https://outlook.office365.com " -TargetAutodiscoverEpr "https://autodiscover-s.outlook.com/autodiscover/autodiscover.svc/WSSecurity "

1. Configure Organization Relationship in Exchange Online:

New-OrganizationRelationship -Name "OnPrem Relationship" -DomainNames "<Your On-Premises Domain>" -FreeBusyAccessEnabled $true -FreeBusyAccessLevel LimitedDetails -TargetApplicationUri "<Your On-Premises Autodiscover URI>" -TargetAutodiscoverEpr "<Your On-Premises Autodiscover EPR>"

5. User Configuration

Ensure that users are properly licensed for Microsoft Teams and have the necessary permissions to access calendars.

Conclusion

By following these steps, you can integrate your on-premises Exchange Server calendar with Microsoft Teams in a hybrid environment. This integration enables seamless calendar access and synchronization, enhancing collaboration and productivity across your organization. Make sure to regularly verify the configuration and monitor for any issues to maintain smooth operation.