Exam MB-240 topic 1 question 238 discussion

A addresses the most likely cause: the technicians’ security roles. The "Field Service - Offline Resource" role (or a similar role like "Field Service - Resource") is required for mobile app access, especially for offline use. If technicians don’t have this role, they’re blocked from logging in. The second part ("assigned to the app") is imprecise but could broadly mean ensuring the role aligns with the app’s permissions in the App Module settings. This is a common UAT issue—roles not assigned correctly during testing. B is relevant only if the app is in offline mode and the profile excludes the users, but the error suggests a login failure, not an offline sync issue. It's a secondary consideration. C is an end-user action, not an admin troubleshooting step, and doesn’t apply since technicians can’t log in. D misunderstands Dynamics 365 configuration—offline profiles don't manage security roles.