Teams App Won't Authenticate in New Outlook

Hi bmedenwald,

To address your Teams app's authentication issue in the new Outlook client, ensure your authentication flow works in both old and new versions of Outlook. If the process redirects to a web browser instead of opening a window in Outlook, follow these steps:

1. Update Authentication Flow: Ensure compatibility with the new Outlook client and handle authentication within Outlook itself.
2. Use MSAL: Implement the Microsoft Authentication Library (MSAL) for seamless authentication and token acquisition.
3. Handle Callbacks: Properly manage authentication callbacks to redirect back to Outlook after completing the process.
4. Test and Debug: Thoroughly test in both Outlook versions and use developer tools for debugging. 

Sample Code Snippet using MSAL:

const msalConfig = {
 auth: {
   clientId: 'your_client_id',
   authority: 'https://login.microsoftonline.com/your_tenant_id',
 }
};
const msalInstance = new msal.PublicClientApplication(msalConfig);
const loginRequest = { scopes: ['user.read'] };
msalInstance.loginPopup(loginRequest)
 .then(response => {
   console.log('Authentication successful:', response);
 })
 .catch(error => {
   console.error('Authentication error:', error);
 });

Please refer the MSAL Documentation and Authentication in Microsoft Teams Apps documents. These steps should resolve the authentication issue in the new Outlook client, ensuring a consistent user experience.