Asking 'Can you access network resources from a different device using your current credentials?' helps to isolate whether the problem is with the user's machine or their account. If the user can access resources from another machine using the same credentials, this indicates that the account is likely in good standing and shifts focus to potential issues with the user's primary machine. Other options are less effective as they either do not distinguish between machine and account issues, focus on irrelevant details, or suggest actions that may not yield diagnostic information.