Microsoft 365 Admin Decoder Fast answers for working admins
AADSTS50105

User is not assigned to the application

Answer: The enterprise application requires assignment, but the user or an applicable group is not assigned.
Resolution playbook

Fix it, then prove it

Use the error record as the starting point; use tenant evidence to confirm the actual cause.

1

Likely causes

  • Application assignment and API permission consent are separate controls.
  • Conditional Access, MFA, identity risk, session, tenant routing, or account state changed the authentication decision.
  • The sign-in used a different application, resource, device, location, or authentication flow than the working comparison.
2

Recommended fix

  1. Confirm user assignment is required on the enterprise application.
  2. Assign the appropriate user or group rather than disabling assignment broadly.
  3. Allow time for group membership and assignment changes to propagate.
3

Verify

  1. Repeat the sign-in using the intended tenant and supported interactive or non-interactive flow.
  2. In Entra sign-in logs, confirm the new event succeeds and review Authentication Details and Conditional Access tabs.
  3. If a policy was changed, confirm the expected policy result using report-only or What If before broad rollout.
4

Escalate when

  • The failure persists after the documented prerequisites and a new authentication/session attempt.
  • Multiple users, apps, devices, or networks show the same error, suggesting tenant policy or service scope.
  • You can provide the exact UTC time, tenant, application/resource, correlation or request ID, and sanitized logs.
Capture the support evidence
Error code: AADSTS50105
UTC timestamp: <yyyy-mm-dd hh:mm:ssZ>
Correlation ID: <guid>
Tenant ID: <guid>
Application / resource: <name>

Template only. Fill it from the failed sign-in and keep user identifiers out of public tickets.

Admin context

Application assignment and API permission consent are separate controls.

Evidence to preserve

  • UTC timestamp and correlation/request ID
  • Tenant, application, resource, and authentication flow
  • Sanitized service log details and exact operation
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