How to fix Microsoft Teams 'Unable to join meeting' errors for external guests

Summary

This guide helps you troubleshoot and resolve: How to fix Microsoft Teams 'Unable to join meeting' errors for external guests. Follow the steps below to fix the issue.

Common Causes

It can be frustrating when external clients or partners are unable to join your scheduled Microsoft Teams meetings. This usually occurs due to restrictive tenant settings within your organisation's Microsoft 365 environment or incorrect meeting options that prevent "anonymous" users from entering the call.

Quick Fix Steps

Before diving into administrative settings, try these immediate solutions to get your guest into the meeting:

• Check the Lobby: Look at the Participants pane. If the guest is stuck in the "Lobby", you must manually click Admit to let them in.
• Send a Direct Link: Copy the meeting link from your Teams calendar and email it directly to the guest.
• Web Browser Access: Suggest the guest open the link in an Incognito/InPrivate browser window to avoid conflicts with their own company's Teams account.

Detailed Instructions for Organisers

To prevent these errors for future meetings, you can adjust the specific meeting options to be more permissive for external guests.

Adjusting Meeting Options

1. Open your Teams Calendar and double-click the scheduled meeting.
2. Select Meeting options (usually found in the top toolbar or under the ... More menu).
3. Locate the setting Who can bypass the lobby?.
4. Change this dropdown to Everyone. This allows guests to join immediately without waiting for your approval.
5. Ensure Allow meeting chat is set to Enabled if you want guests to share files or links during the call.
6. Click Save.

Administrative Configuration

If your guests are consistently unable to join any meetings across your organisation, your global tenant settings may be too restrictive. These steps require Global Administrator or Teams Administrator privileges.

Checking Guest Access Settings

1. Log in to the Microsoft Teams Admin Center.
2. Navigate to Users > Guest access.
3. Ensure the toggle for Allow guest access in Teams is set to On.
4. Review the permissions below the toggle (e.g., Allow guest access to chat) to ensure they align with your organisation's security policy.
5. Click Save at the bottom of the page.

Analysing External Access (Federation)

1. In the Admin Center, go to Users > External access.
2. Under Choose which domains your users can communicate with, ensure it is set to Open federation.
3. If you have selected Allow only specific external domains, you must manually add the guest's email domain (e.g., clientcompany.com.au) to the allowed list.

Troubleshooting Common Guest Errors

"You're not invited to this meeting"

This typically happens when a guest tries to join a meeting using a corporate account that has strict "Tenant Restrictions" enforced by their own IT department. The best workaround is for the guest to join as a guest via the web browser rather than the desktop application.

Authentication Loops

If a guest is repeatedly asked to sign in, they may have a cached credential conflict. Advise them to:

• Clear their browser cache and cookies.
• Use a different browser (e.g., switching from Chrome to Edge).
• Join the meeting as a "Guest" by clicking Join on the web instead when the prompt appears.

If you have verified these settings and external users are still unable to connect, it may indicate a broader connectivity issue. If you are experiencing other communication failures, such as Email not sending or receiving, please Open a Ticket for further investigation.

Still Having Issues?