The DHCP server is not available is the most likely cause of the issue where a new computer is unable to ping the default gateway. DHCP stands for Dynamic Host Configuration Protocol, which is a network protocol that automatically assigns IP addresses and other configuration parameters to clients on a network. The default gateway is the IP address of the router or device that connects a local network to other networks, such as the internet. Pinging is a network utility that tests the connectivity and reachability between two devices by sending and receiving echo packets. If the DHCP server is not available, the new computer will not be able to obtain an IP address or other configuration parameters, such as the default gateway, from the DHCP server. This will prevent the new computer from communicating with other devices on the network or the internet, resulting in ping failure. Reference: [CompTIA Network+ Certification Exam Objectives], What Is DHCP? | How DHCP Works | SolarWinds MSP

NIC teaming, also known as network interface card teaming or link aggregation, allows multiple network interface cards to be grouped together to provide redundancy and increased throughput. In the event of a port failure on a switch, NIC teaming ensures that the file server remains connected to the LAN by automatically switching to another network interface card.

A WLAN controller is a device that manages and controls multiple wireless access points (WAPs) in a wireless LAN (WLAN). A WLAN controller has the capability to centrally manage configuration, logging, and firmware versioning for distributed WAPs. A WLAN controller can also provide load balancing, security, and quality of service (QoS) for the WLAN.

Port mirroring is a method of monitoring network traffic by copying the data packets from one port to another port on the same switch or router. This allows the network security administrator to analyze the contents of the data sent between different networks without affecting the performance or security of the original traffic. Port mirroring can be configured to capture all traffic or only specific types of traffic, such as VLANs, protocols, or IP addresses.
Reference:
Port Mirroring - CompTIA Network+ N10-008 Domain 3.1 - YouTube1
CompTIA Network+ Certification Exam Objectives, page 142

A layer 3 switch is a device that can perform both switching and routing functions. It can forward packets based on the destination IP address, which is the information used to identify different subnetworks. A layer 3 switch can also create and manage multiple VLANs, which are logical subnetworks within a physical network. Therefore, a layer 3 switch can allow communication between two different subnetworks.
A router is a device that connects multiple IP networks and forwards packets based on the destination IP address. A router can also perform network address translation (NAT), which allows devices with private IP addresses to communicate with devices with public IP addresses. Therefore, a router can allow communication between two different subnetworks, especially if they use different address spaces.
An IDS (intrusion detection system) is a device that monitors network traffic and detects malicious or anomalous activities. An IDS does not forward packets or allow communication between subnetworks, but rather alerts the network administrator or takes preventive actions when a threat is detected.
An access point is a device that allows wireless devices to connect to a wired network. An access point does not forward packets or allow communication between subnetworks, but rather acts as a bridge between the wireless and wired segments of the network.
A layer 2 switch is a device that forwards frames based on the destination MAC address, which is the information used to identify devices within the same subnetwork. A layer 2 switch does not perform routing or network segmentation, and therefore cannot allow communication between different subnetworks.
A media converter is a device that converts signals between different types of media, such as copper and fiber. A media converter does not forward packets or allow communication between subnetworks, but rather enables devices with different physical interfaces to connect to the same network.
Reference:
Network Devices
Routing and Switching Essentials
CompTIA Network+ N10-008 Study Guide, Chapter 2: Devices and Infrastructure, pages 58-63, 72-75.