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Hi Michael Battle,
Welcome to Microsoft Q&A Forum! Have a good day and I hope you're doing well!
I understand how frustrating it can be when you’re trying to access an application and encounter a sign-in error.
Based on my research, the “external tenant” message typically appears when the account used to sign in does not match the one that was granted access.
To start, please try the following steps:
- Sign out of all Microsoft accounts in your browser.
- Open a private browsing window.
- Sign in again using the exact email address that received the invitation.
If you still receive the “external tenant” error after trying the steps above, the issue is likely related to permissions on the sender’s organization side. I recommend contacting the person who shared the application and asking them to confirm:
- That your email address has been added to their organization as a Guest (external user), and
- That you have been granted the appropriate access to the SharePoint site, app, or Team.
They may need to review the guest access settings in Microsoft Entra ID (Azure AD) or reshare the application with the correct email address to ensure permissions are properly assigned.
Additionally, could you please provide a full screenshot of the detailed error message? This will give me more insight and help me suggest more precise troubleshooting steps.
I hope this will at least partially help move things forward. If you have any updates or if I’ve misunderstood anything, please feel free to let me know. I’m happy to continue assisting you.
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