Incident: Planner tabs fail to load in Microsoft Teams (Desktop and Web)

Affected service: Microsoft Teams / Microsoft Planner Issue start date: November 9, 2026 Scope: Multiple users across the organization Severity: Business impact – multiple users affected

Problem description

Since November 9, 2026, Microsoft Planner tabs in Microsoft Teams have stopped loading for multiple users across our organization.

The issue affects both:

Microsoft Teams Desktop

Microsoft Teams Web

When users attempt to open automatically created Planner tabs within Teams channels, the following error message appears:

"Beim Erreichen dieser App gab es ein Problem."

The affected Planner plans and tasks are accessible through other entry points in some circumstances, but the Planner tabs within Teams do not load correctly.

Important finding – reproducible workaround

We discovered an unusual behavior:

Automatically created Planner tabs initially fail to open.

We manually create a new Planner plan and add it as a tab to a Teams channel.

After opening this manually created Planner tab once, all previously inaccessible Planner tabs across other channels and projects become accessible again.

This behavior has been observed in both Teams Desktop and Teams Web.

Opening the standalone Planner application through the Teams left navigation does not resolve the issue.

After completely signing out of Teams and signing in again, the problem returns.

This suggests that opening a manually created Planner tab triggers some kind of initialization or refresh of the Planner integration within Teams.

Troubleshooting already performed

Cleared the Teams cache.

Completely signed out of Teams and signed in again.

Restarted the Teams client.

Tested Teams Desktop and Teams Web.

Tested different Teams channels.

Changed the channel layout (Threads / Posts).

Confirmed that other channel tabs, such as Notes, can still open.

None of these actions permanently resolved the issue.

Automation and configuration

Planner plans, tasks and Teams tabs are created automatically using Microsoft Power Automate and Microsoft Graph API.

The automatically created tabs use the Microsoft Planner Teams application:

com.microsoft.teamspace.tab.planner

The automation successfully creates the plans and tabs. The same tabs have previously worked correctly.

We currently have no evidence that the Power Automate flow or the Graph API requests are responsible for this issue.

Possible cause

The issue appeared simultaneously for multiple users on November 9, 2026.

We would like Microsoft to investigate whether a recent Planner application update, Teams client update, backend deployment or regression in the Planner–Teams integration could have caused this behavior.

Assistance requested from Microsoft

Please investigate:

Whether there were any recent changes or deployments affecting Planner tabs in Microsoft Teams around November 9, 2026.

Whether there are known issues with Planner tab initialization, application context or authentication.

Why opening one manually created Planner tab restores access to all previously inaccessible Planner tabs across different Teams channels.

Whether this behavior is related to a backend service issue or a recent Planner application regression.

Whether a service-side fix or configuration change is required.

We would appreciate a technical investigation and, if possible, confirmation of the root cause.

This issue affects multiple users and significantly impacts access to our project management environment.

Incident: Planner tabs fail to load in Microsoft Teams (Desktop and Web)

Affected service: Microsoft Teams / Microsoft Planner
Issue start date: November 9, 2026
Scope: Multiple users across the organization
Severity: Business impact – multiple users affected

Problem description

Since November 9, 2026, Microsoft Planner tabs in Microsoft Teams have stopped loading for multiple users across our organization.

The issue affects both:

Microsoft Teams Desktop

Microsoft Teams Web

When users attempt to open automatically created Planner tabs within Teams channels, the following error message appears:

"Beim Erreichen dieser App gab es ein Problem."

The affected Planner plans and tasks are accessible through other entry points in some circumstances, but the Planner tabs within Teams do not load correctly.

Important finding – reproducible workaround

We discovered an unusual behavior:

Automatically created Planner tabs initially fail to open.

We manually create a new Planner plan and add it as a tab to a Teams channel.

After opening this manually created Planner tab once, all previously inaccessible Planner tabs across other channels and projects become accessible again.

This behavior has been observed in both Teams Desktop and Teams Web.

Opening the standalone Planner application through the Teams left navigation does not resolve the issue.

After completely signing out of Teams and signing in again, the problem returns.

This suggests that opening a manually created Planner tab triggers some kind of initialization or refresh of the Planner integration within Teams.

Troubleshooting already performed

Cleared the Teams cache.

Completely signed out of Teams and signed in again.

Restarted the Teams client.

Tested Teams Desktop and Teams Web.

Tested different Teams channels.

Changed the channel layout (Threads / Posts).

Confirmed that other channel tabs, such as Notes, can still open.

None of these actions permanently resolved the issue.

Automation and configuration

Planner plans, tasks and Teams tabs are created automatically using Microsoft Power Automate and Microsoft Graph API.

The automatically created tabs use the Microsoft Planner Teams application:

com.microsoft.teamspace.tab.planner

The automation successfully creates the plans and tabs. The same tabs have previously worked correctly.

We currently have no evidence that the Power Automate flow or the Graph API requests are responsible for this issue.

Possible cause

The issue appeared simultaneously for multiple users on November 9, 2026.

We would like Microsoft to investigate whether a recent Planner application update, Teams client update, backend deployment or regression in the Planner–Teams integration could have caused this behavior.

Assistance requested from Microsoft

Please investigate:

Whether there were any recent changes or deployments affecting Planner tabs in Microsoft Teams around November 9, 2026.

Whether there are known issues with Planner tab initialization, application context or authentication.

Why opening one manually created Planner tab restores access to all previously inaccessible Planner tabs across different Teams channels.

Whether this behavior is related to a backend service issue or a recent Planner application regression.

Whether a service-side fix or configuration change is required.

We would appreciate a technical investigation and, if possible, confirmation of the root cause.

This issue affects multiple users and significantly impacts access to our project management environment.