Teams app on Android: AADSTS90023: An error occurred while processing incoming message.

I will answer you in English based on your previous message. As a friendly suggestion, posting Norwegian in may help your question reach a wider audience and increase the chances of receiving assistance from other community members.

Hi wimow,

Based on your description, the error AADSTS90023: "An error occurred while processing incoming message" commonly occurs when a guest user attempts to sign in to or switch organizations (B2B tenants) in the Microsoft Teams mobile app. This is often related to token validation or token cache conflicts between different organizations on the mobile device.

To troubleshoot the issue, you may try the following steps on one of the affected Android devices:

1. Open Settings > Apps > Microsoft Teams.
2. Select Storage, then choose Clear cache and Clear storage/Clear data.
3. If installed, repeat these steps for Microsoft Authenticator and Company Portal. Important: Please do not clear Microsoft Authenticator data unless the user has another available verification method or an administrator can reset their authentication methods. Clearing Authenticator data removes all accounts from the app and may prevent the user from completing future sign-ins
4. Ensure that the following components are fully updated:
   • Microsoft Teams
   • Microsoft Authenticator / Company Portal (if applicable)
   • Google Chrome
   • Android System WebView
   • Android OS
5. Restart the device, open Teams, and sign in using the guest user's home account first. After signing in successfully, switch to your organization from the account/organization menu.
6. Temporarily disable any VPN connection and verify that the device's date and time are configured automatically. Microsoft also recommends checking application versions, connectivity, and device updates when troubleshooting authentication-related issues.

If the issue persists after performing these steps, it may require further investigation from Microsoft's support team.

If you are the IT administrator, please open a support request through: Microsoft 365 Admin Center > Support > Help & Support. If you are not the IT administrator, I recommend contacting your IT administrator and asking them to open a support request on your behalf.

You can follow the guidance in the following article:

Get support - Microsoft 365 admin | Microsoft Learn

I hope you can understand that, as a forum moderator, I do not have access to Microsoft's backend systems or internal diagnostic tools. The Microsoft Support team has a higher level of access and the appropriate escalation channels to investigate this issue from the service side and review any backend authentication-related problems. This would be the most effective and efficient way to resolve the issue for you and your guest users.

I hope this helps. Please let me know if you have any questions or if there's any update after trying the above steps.