How to Fix the Broken Connection Between Exchange Calendar and Microsoft Teams

By João Ferreira Jun 17, 2025 Devices, Meetings 0 Comments

Recently, I encountered an interesting connectivity challenge between Exchange calendars and Microsoft Teams. One day, everything was running smoothly when suddenly my Teams room devices began experiencing issues. If this sounds familiar, let me share the troubleshooting journey and solution that could save you considerable time.

The Issue: Intermittent Calendar Integration

A couple weeks ago, I began noticing unusual behavior with the connectivity between my Microsoft Teams room devices and the Teams display on my desk. None of the accounts in my tenant could retrieve information from the Exchange calendar.

What made this particularly puzzling was that I could still view my appointments in Teams and schedule regular meetings without issues. However, attempting to schedule a town hall failed consistently, indicating a deeper connectivity problem between Teams and Exchange.

Diagnostic Approach

My first step was verifying that all accounts had proper Exchange licenses assigned, which they did. This ruled out the most obvious cause.

To properly diagnose the Teams-Exchange connectivity, I utilized the Microsoft Remote Connectivity Analyzer. This tool provides comprehensive testing for Teams-Exchange integration.

The error message was crystal clear: “The user’s mailbox is not discoverable by the Teams service. Make sure user has Exchange Web Services (EWS) and REST API protocols enabled.”

Root Cause: Microsoft EWS Policy Change

This error led me to discover that Microsoft recently implemented a significant change to EWS behavior. Previously, organizations could disable EWS at the organizational level while enabling it for individual users. My tenant was configured this way and had been functioning properly until this change.

The new policy establishes that organization-level settings now take precedence over user-level settings. Microsoft documented this change in their technical community post.

The Solution: PowerShell Configuration

Resolving this issue requires using Exchange PowerShell to modify the organization-level EWS setting. Here’s the step-by-step process:

Execute these commands in PowerShell (run as administrator):

1. Install the Exchange Online Management module

   Install-Module -Name ExchangeOnlineManagement -RequiredVersion 3.8.0

2. Import the module

   Import-Module ExchangeOnlineManagement

3. Connect to Exchange Online (replace with your admin account)

   Connect-ExchangeOnline -UserPrincipalName your-admin@yourcompany.com

4. Check current EWS setting (probably shows ‘False’)

   Get-OrganizationConfig | fl EwsEnabled

   

5. Enable EWS for the organization

   Set-OrganizationConfig -EwsEnabled:$true

Implementation Timeline

It’s important to note that this configuration change requires propagation time. The changes won’t take effect immediately across Microsoft’s infrastructure. In my environment, Teams devices resumed normal calendar functionality and webinar scheduling capabilities after approximately 8 hours.