External users cannot login, or use apps

Question

We're inviting external users in teams, but they cannot log in, we get an error "account does not exist" and "user not found".
We can accept the invitation, but they have no access to teams, and they cannot log in again after they accept the invitation.

There appears to be something wrong. How do I get support?

Answer 1

Hello @44785390,

The issue where external users accept an invitation to Microsoft Teams but then encounter errors like "account does not exist" or "user not found" typically stems from problems in how those users are invited, provisioned, or authenticated. Although the invitation email might be successfully received and accepted, if users are unable to access Teams or log in afterward, there could be several contributing factors. One of the most common reasons is that the user is not correctly registered as a Guest in Entra ID. When a user is invited externally, AAD creates a guest user object, if this process fails, or if the user is deleted, blocked, or the account gets corrupted, they won’t be able to sign in properly. This issue might also occur if the guest user is trying to log in with an email address or identity different from the one used during the invitation such as trying to sign in with a work account when the invitation was sent to a personal Gmail or Outlook.com address.

To troubleshoot, log into the Microsoft Entra admin center, navigate to Users, and search for the guest account. Confirm that the user is listed, has the user type set to "Guest," and the account is enabled. If the account appears to be stuck in a "Pending" or broken state, you should consider deleting and reinviting the user. Before doing so, advise the user to clear their browser cookies or use an incognito/private window to avoid conflicts with cached credentials. After deletion, send a new invitation and ensure they are logging in with the exact email address that was invited.

Next, review your organization’s External Collaboration Settings by navigating to Azure Active Directory > External Identities > External Collaboration Settings. Ensure that guest users are allowed to be invited, that domain restrictions are not blocking the user's email domain, and that settings such as “Guests can access Microsoft Teams” are properly enabled. Also, check Teams Admin Center > Org-wide Settings > Guest Access to confirm that guest access is turned on for Microsoft Teams and that required settings such as "Allow guest access in Teams" are enabled.

If issues persist, it's helpful to test login from the user’s side using the direct URL https://teams.microsoft.com, as well as sharing a direct link to the specific team or channel they've been added to. If they receive a message like "You're not authorized" or "Team not found," it may point to an issue with permissions or a delay in propagation. Ensure the user has been explicitly added to the correct Team within Teams, and not just to the organization via Azure.

Kindly do let us know if you have any questions or query.