The most likely cause of the issue is that the server has not been joined to the domain. A domain is a logical group of computers and devices that share a common directory service and security policy. A domain controller is a server that manages the domain and authenticates users and computers that want to access domain resources. To log on with domain credentials, a server must be joined to the domain and registered in the directory service. If a server has not been joined to the domain, it will not be recognized or authorized by the domain controller.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 4, Lesson 4.3, Objective 4.3

Archive is a method of storing historical data that is not frequently accessed or modified. Archive can reduce the amount of data that needs to be backed up and save bandwidth and storage space. Differential is a method of backing up only the data that has changed since the last full backup. Differential can also save bandwidth and storage space, as well as speed up the backup process.
References:
CompTIA Server+ Certification Exam Objectives1, page 12
Server Management: Server Hardware Installation and Management2, Module 2, Lesson 5

iSCSI is a protocol that allows SCSI commands to be transmitted over IP networks, enabling remote access to storage devices. iSCSI uses IP addresses to identify and communicate with the storage array, so having multiple IP addresses for the array indicates that iSCSI is being used. eSATA, USB, and FC are other types of connections that use different protocols and connectors than iSCSI. References: CompTIA Server+ Certification Exam Objectives, Domain 3.0: Storage, Objective 3.1: Given a scenario, install and deploy primary storage devices based on given specifications and interfaces.

The first action that the administrator should take before swapping out the GPU card inside a server is to shut down the server. This is to ensure that the server is not running any processes that might be using the GPU card, and to prevent any damage to the hardware or data loss due to sudden power loss. Shutting down the server also reduces the risk of electrostatic discharge (ESD) that might harm the components. Reference:
https://pcgearhead.com/installing-a-new-gpu/

Two-person integrity is a security measure that can be implemented to increase security against a potential insider threat on an air-gapped system. An air-gapped system is a system that is isolated from any network connection and can only be accessed physically. An insider threat is a malicious actor who has authorized access to an organization's system or data and uses it for unauthorized or harmful purposes. Two-person integrity is a system of storage and handling that requires the presence of at least two authorized persons, each capable of detecting incorrect or unauthorized security procedures, for accessing certain sensitive data or material. This way, no single person can compromise the security or integrity of the data or material without being noticed by another person. SSO (Single Sign-On) is a feature that allows users to access multiple applications or systems with one set of credentials, but it does not prevent insider threats. SIEM (Security Information and Event Management) is a tool that collects and analyzes log data from various sources to detect and respond to security incidents, but it does not work on air-gapped systems. A Faraday cage is a structure that blocks electromagnetic signals from entering or leaving, but it does not prevent physical access or insider threats. MFA (Multi-Factor Authentication) is a method that requires users to provide two or more pieces of evidence to verify their identity, such as something they know, something they have, or something they are, but it does not prevent insider threats. References: https://www.howtogeek.com/169080/air-gap-how- to-isolate-a-computer-to-protect-it-from-hackers/ https://www.howtogeek.com/428483/what-is-end-to-end- encryption-and-why-does-it-matter/ https://www.howtogeek.com/202794/what-is-the-difference-between-
127.0.0.1-and-0.0.0.0/ https://www.howtogeek.com/443611/how-to-encrypt-your-macs-system-drive- removable-devices-and-individual-files/