If a customer is not receiving messages via iMessage, what setting should be checked?

When a customer is not receiving messages via iMessage, the first step in diagnosing the issue involves checking the iMessage settings. These settings include ensuring that iMessage is enabled on the device, confirming that the correct Apple ID is being used, and verifying that the device is connected to either Wi-Fi or a cellular data network.

These settings are crucial because if iMessage is turned off, or if there are any restrictions or configuration issues with the Apple ID, it can prevent messages from being sent or received. Additionally, verifying that the customer has enabled "Send as SMS" in case iMessage is unavailable can help in troubleshooting the problem effectively.

While other options may play a role in overall messaging functionality, focusing on the iMessage settings directly addresses the core aspect of Apple’s messaging platform, making it the most relevant choice when dealing with iMessage issues.