authentication fails with the following error: Error code: AADSTS50020

The error values show that New Outlook is sending the personal live.com identity to an unintended organizational tenant, so remove that tenant’s cached Windows/Office connection and then add the active @iafrica.com mailbox as the provider-hosted email account rather than as an organizational Microsoft 365 account.

1. Remove the unintended organizational connection

1. Close New Outlook and all other Microsoft 365 applications.
2. Open Windows Settings → Accounts → Access work or school.
3. If an account associated with Tubular Technical Construction (Pty) Ltd appears, expand it and select Disconnect → Yes.
   • Do not disconnect an account that is still needed for the client’s work.
   • Disconnecting removes its sign-in information from the device; it does not delete the organizational account. ^1^
4. Open Control Panel → Credential Manager → Windows Credentials.
5. Remove saved Office/Microsoft credentials clearly associated with the unwanted tenant or obsolete organizational account. Do not remove unrelated credentials.
6. Restart Windows.

The User account and Identity provider fields in AADSTS50020 are the relevant checks for wrong-tenant selection. Here, live.com identifies the personal Microsoft identity while the named resource tenant is the organization the client does not intend to access. Microsoft’s documented resolution for wrong-account or wrong-tenant sessions is to sign out and authenticate again without the conflicting session. ^2^

The application ID [GUID] is a Microsoft Office/Outlook client identifier; it is not evidence that the mailbox itself belongs to that company tenant. ^3^

2. Remove and re-add the mailbox safely

In New Outlook:

1. Select View → View settings, or File → Account info.
2. Open Accounts → Your accounts.
3. Beside the @iafrica.com account, select Manage → Remove.
4. Choose Remove from this device, not Remove from all devices.
5. Return to Accounts → Your accounts → Add Account.
6. Enter the complete @iafrica.com address and continue through the provider account setup.

Removing it from Outlook does not delete the provider mailbox. However, Remove from all devices can remove Microsoft Cloud data across Outlook clients, including items that exist only there, so avoid that option. ^4^

New Outlook supports third-party accounts connecting through IMAP. Obtain the correct incoming server, outgoing SMTP server, ports, encryption methods, username format, and any required app password directly from the iafrica.com mail provider. ^5^

The Microsoft 365 Family sign-in licenses the Office applications; it does not move the provider-hosted @iafrica.com mailbox or its historical messages into Microsoft 365. Because webmail still contains the messages, removing only the Outlook account should not affect that server-side history.

3. If New Outlook still invokes the company tenant

Repair the Windows personal-account authentication component:

1. Right-click Start and open Windows PowerShell (Admin).
2. Run:

if (-not (Get-AppxPackage Microsoft.Windows.CloudExperienceHost)) {
    Add-AppxPackage -Register `
      "$env:windir\SystemApps\Microsoft.Windows.CloudExperienceHost_cw5n1h2txyewy\Appxmanifest.xml" `
      -DisableDevelopmentMode -ForceApplicationShutdown
}
Get-AppxPackage Microsoft.Windows.CloudExperienceHost

3. Restart Windows and add the account again.

Microsoft documents this Live ID package repair for personal-account authentication failures in Microsoft 365 applications. ^6^

Support route

Start with Microsoft Consumer Support / Microsoft 365 Family technical support, because:

• The subscription is Microsoft 365 Family.
• The failing client is New Outlook.
• The client does not want access to the named organizational tenant.
• The mailbox remains available through its provider.

Microsoft Entra Support or the named organization’s administrator is relevant only if the client genuinely must access an application in that tenant as a guest. Do not ask that organization to add the personal account merely to make a provider-hosted mailbox work.

When opening the consumer case, provide the complete AADSTS50020 text, UTC timestamp, request ID, correlation ID, Windows version, New Outlook version, and confirmation that the mailbox works in provider webmail. Redact the email address and identifiers from public posts. Consumer support routes home-product technical issues through the Microsoft support entry point. ^7^

References

1. Manage User Accounts in Windows | Microsoft Support
2. Error AADSTS50020 - User account from identity provider does not exist in tenant
3. Configure your tab app in Microsoft Entra ID
4. [New Outlook](https://support.microsoft.com/outlook/getstarted/add-an-email-account-to-outlook-for-windows#remove-an-account-in-new-outlook)
5. Start using new Outlook for Windows | Microsoft Support
6. Fix authentication issues in Microsoft 365 apps when you try to connect to a Microsoft 365 service
7. Contact Microsoft customer support | Microsoft Support