Microsoft Teams iOS app fails to sign in with personal Microsoft account (Error 965yb – Access denied for the resource)

I’m unable to sign in to the Microsoft Teams iOS app using my personal Microsoft account (Gmail address, originally created from a Skype account).

Expected behavior

The Teams app should sign in successfully and display my chats.

Actual behavior

The sign-in always fails with:

Something went wrong. [965yb]

Message: Access denied for the resource.

Environment

• Device 1: iPhone 14 Pro
• Device 2: iPhone 13
• iOS: 26.5
• Latest Microsoft Teams app from the App Store
• Personal Microsoft account (not a work or school account)

What I have verified

• I can sign in to account.microsoft.com successfully.
• Microsoft Authenticator works correctly.
• I can sign in to https://teams.live.com and access all my chats.
• The problem only occurs in the iOS Teams app.

Troubleshooting already attempted

• Reinstalled Teams.
• Cleared Teams app data.
• Restarted both iPhones.
• Signed out from Teams on the second iPhone and attempted to sign in again.
• The same error now occurs on both devices. Environment
  • Device 1: iPhone 14 Pro
    • Device 2: iPhone 13
      • iOS: 26.5
        • Latest Microsoft Teams app from the App Store
          • Personal Microsoft account (not a work or school account)
  What I have verified
  • I can sign in to account.microsoft.com successfully.
    • Microsoft Authenticator works correctly.
      • I can sign in to https://teams.live.com and access all my chats.
        • The problem only occurs in the iOS Teams app.
  Troubleshooting already attempted
  • Reinstalled Teams.
    • Cleared Teams app data.
      • Restarted both iPhones.
        • Signed out from Teams on the second iPhone and attempted to sign in again.
          • The same error now occurs on both devices.

Is this a known issue with Teams Personal on iOS, or is there anything else I can try?