A cloud-based identity and access management service for securing user authentication and resource access
If the sign-in or risky user entry shows only a User ID / Object ID / GUID instead of a username, the documented causes are:
- Passwordless authentication
Check the sign-in event details. If theauthenticationDetailfield sayspasswordless, the User ID can appear instead of the username. - The user authenticated but has not yet completed sign-in
Check whether the event has error code 50058. That correlates with an interrupt and can cause the username field to show an ID instead. - Tenant restrictions
If the username field shows something like000000-00000-0000-0000, tenant restrictions may be preventing sign-in to the selected tenant. - Aggregation delay for multifactor authentication events
MFA sign-in attempts can be aggregated from multiple data entries. It can take up to two hours for the username to display properly.
For investigation, open the risky sign-in details and review the event fields, especially authenticationDetail and the error code. If this is a risky user entry, review the user’s risky sign-ins and risk history from Microsoft Entra ID > Security > Risky users.