Final answer:
The first troubleshooting step to advise when a customer's issue cannot be duplicated is to restart the device, a simple action that can clear temporary files and refresh content loaded into memory.
Step-by-step explanation:
When troubleshooting an issue that a technical support team cannot duplicate, the first step that should be advised is to restart the device. Restarting can resolve a surprising number of problems by clearing temporary files, resetting the device's state, and establishing new network connections.
It is essentially a way to refresh the content loaded into the device's memory. If the issue persists after a restart subsequent steps might include checking the internet connection clearing cache and cookies or updating the software to ensure the device is running optimally and securely.