Do you have the same issue when login Teams web client?
To resolve this issue, you need to add the user account as an external user in the tenant. This can be done by following these steps:
- Log in to the Azure portal using an account that has the necessary permissions to add external users.
- Navigate to the Azure Active Directory blade.
- Click on the 'Users' blade.
- Click on the 'New guest user' button.
- Fill in the required details for the new user and invite them to the tenant.
- Once the user has accepted the invitation and their account has been created in the tenant, they should be able to access the application using their account.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.