The methods that would allow the administrator to perform maintenance on all 12 servers without having to physically be at each server are remote desktop and IP KVM. Remote desktop is a feature that allows a user to access and control another computer over a network using a graphical user interface (GUI). Remote desktop can enable remote administration, troubleshooting, and maintenance of servers without requiring physical presence at the server location. IP KVM (Internet Protocol Keyboard Video Mouse) is a device that allows a user to access and control multiple servers over a network using a single keyboard, monitor, and mouse. IP KVM can provide remote access to servers regardless of their operating system or power state, and can also support virtual media and serial console functions.
Reference:
https://www.blackbox.be/en-be/page/27559/Resources/Technical-Resources/Black-Box-Explains/kvm/ Benefits-of-using-KVM-over-IP

The most likely cause of the server crashing and the application being inaccessible is that the unauthorized software installed by the update is malware that corrupted the system files or compromised the security of the server. To restore access to the application while minimizing downtime, the administrator should scan and remove any malware from the server, and then reformat the server and restore the image from the latest back-up. This will ensure that the server is clean and has a working configuration of the application. Verified References: [How to Remove Malware from a Server]

The HCL stands for Hardware Compatibility List and it is a list of hardware devices that are tested and certified to work with a specific operating system. If a network card is not on the HCL for the OS, it may not function properly or cause compatibility issues. Therefore, verifying the network card is on the HCL for the OS should be the next step to troubleshoot this issue. References: https://www.comptia.org/training/resources/exam-objectives/comptia-server-sk0-005-exam-objectives (Objective 4.1)