why i cannot access school guest teams account

Dear @Smith Simo,

I understand you can sign into your regular Microsoft Teams account, but you cannot access the guest organization you were invited to. When you try to sign in, Microsoft Authenticator does not provide a verification code and you receive messages indicating the account does not exist, even though you are using the same email address.

Guest access in Microsoft Teams is managed inside the host organization’s Microsoft Entra ID directory. Although you use the same email, your guest identity is separate from your home account. If multi‑factor authentication for the host tenant is not set up for your guest identity, or if the sign‑in is using cached credentials from your home tenant, you may see “account doesn’t exist” errors or you may not receive verification prompts.

You can take the following steps to address the issue:

1. Sign out of all Teams sessions
   • On desktop: Click your profile picture > Sign out. Close the app completely.
   • On web: Sign out at teams.microsoft.com, then close the browser.
2. Accept or re‑accept the guest invitation
   • Locate the original invitation email from the host organization and click Accept.
   • If you can’t find it, ask the host admin to resend the guest invitation. (This refreshes your guest account in their tenant.

If it still doesn’t work, you should reach out to the host admin.

The host admin should:

• Confirm your guest user exists and is Enabled in Microsoft Entra ID.
• Remove and re‑invite your guest user or reset MFA for the guest.
• Check Conditional Access policies that might block guest sign‑in (e.g., device compliance required).

Please refer to this document: B2B guest user properties - Microsoft Entra External ID | Microsoft Learn

Note: Your regular Teams account and your guest Teams account are managed by two separate tenants. Make sure you contact the correct person, either the admin or owner in the guest tenant, who is responsible for inviting and managing your guest access.

Quick tips

• Using Incognito/Private mode is the fastest way to rule out cached sign‑in conflicts.
• If you have multiple Microsoft accounts on the device, choose “Sign in with another account” during login and explicitly select the guest organization when prompted.
• The Authenticator app can hold multiple work/school identities, make sure the one for the host org appears and is verified.

I hope this provides enough clarity and helps you stay inform with your current situation.

Thank you for your patience and your understanding. 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. 

If the answer is helpful, please click "Yes" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

Note: Please follow the steps in the forum document to enable e-mail notifications if you want to receive the related email notification for this thread.