Using the New Outlook for Mac features in business environments
Hi Dr. Josie,
According to Error AADSTS50020 - User account from identity provider does not exist in tenant | Microsoft Learn, Outlook on your iPad appears to be trying to sign in with a Microsoft identity that is not being recognized by your organization’s Microsoft environment.
It could be due to the account you're using must first be added as a guest in the tenant before you can be granted access to Outlook. This action can only be performed by the organization’s admin. If you are an admin, you can follow the steps below; if you are a user, please contact your organization’s admin for assistance.
If you are an Entra ID/M365 Admin, please invite the guest to the tenant (Entra ID)
- Go to Entra admin center > Microsoft Entra ID > Users > New user > Invite external user.
- Enter the guest’s email address, provide a display name, and send the invitation.
- Reference link: Quickstart: Add a guest user and send an invitation - Microsoft Entra External ID | Microsoft Learn
Additionally, they can verify the user access to the application, see Assign a user account to an enterprise application.
In the meantime, you can try sign in to your account from your iPad by opening a new in-private browser session or access from a different browser. In this case, you should sign out from your active session, clear your default browser and apps cache, and then try to sign in again.
For reference: Clear your cache and cookies on iPad - Apple Support
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I hope this provides enough clarity and helps you stay inform with your current situation.
If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.