Microsoft 365 Alert – Service Degradation – Microsoft Teams – Users may see a message “Classic Teams is no longer available” when opening Microsoft Teams through web applications – RESOLVED

Announcements Shagufta Naaz

22/12/2025 11:35:00 AM

NHSmail Reference: INC46710488

Microsoft Reference: TM1202521

Issue Status: RESOLVED

Issue Description: Users may see a message “Classic Teams is no longer available” when opening Microsoft Teams through web applications.

More info: Specifically, when users attempted to open Microsoft Teams through web apps such as Outlook, OneNote, or SharePoint Online, they may have been redirected and received the following message, “Classic Teams is no longer available”. However, users could either click “Use Teams on the web” or directly open the Microsoft Teams app through their mobile, desktop or web app.

Final Update: 22/12/2025 11:37:00 AM – Microsoft has confirmed that a URL mismatch led to Microsoft Teams launching an outdated web page, which resulted in impact. They have changed the URL destination to the correct web page and confirmed through extensive testing, that impact has been remediated.

Scope of impact: Some users attempting to open Microsoft Teams through various web applications may have been impacted.

Root Cause: A URL mismatch led to Microsoft Teams launching an outdated web page.

Next steps: Microsoft are analysing Microsoft Teams URLs on the affected infrastructure to help prevent this problem from happening again.