Explanation
The best solution to investigate the failure of a server in a remote datacenter is out-of-band management.
Out-of-band management is a method of accessing and controlling a server or a device using a dedicated channel that is separate from its normal network connection. Out-of-band management can use various technologies, such as serial ports, modems, KVM switches, or dedicated management cards or interfaces.
Out-of-band management can provide remote access to servers or devices even when they are powered off, unresponsive, or disconnected from the network. Out-of-band management can enable troubleshooting, configuration, maintenance, or recovery tasks without requiring physical presence at the server location.