This is the most likely cause of the issue where the access points in a Microbranch group are online in Aruba Central, but no VPN tunnels are forming. A Microbranch group is a group that contains both APs and Gateways and allows them to form VPN tunnels for secure communication. The VPN tunnels use GRE (Generic Routing Encapsulation) as the encapsulation protocol and IPSec as the encryption protocol. If there is a firewall blocking GRE traffic between the AP and the gateway, the VPN tunnels cannot be established. The other options are incorrect because they either do not affect the VPN tunnel formation or do not apply to a Microbranch group.

According to the Aruba Campus Access Professional documents1, WPA3-Enterprise is a security mode that supports 802.1X authentication and encryption with either AES-CCM or AES-GCMP. WPA3-Enterprise also optionally adds usage of Suite-B 192-bit minimum-level security suite that is aligned with Commercial National Security Algorithm (CNSA) for enterprise networks2. This mode provides the highest level of security and is suitable for government and financial institutions.
The exhibit shows that the SSID is configured with WPA3-Enterprise (CCM), which uses AES-CCM as the encryption protocol. However, this mode is not compatible with some devices that require CNSA compliance. Therefore, changing the SSID to WPA3-Enterprise (CNSA) would fix the issue and allow all devices to connect to the network.

Explanation
EVPN-VXLAN is a technology that allows layer-2 communication across layer-3 networks by using Ethernet VPN (EVPN) as a control plane and Virtual Extensible LAN (VXLAN) as a data plane3. EVPN-VXLAN can be used to support legacy applications that communicate at layer-2 across different campuses or data centers that are connected via layer-3. EVPN-VXLAN minimizes flooding by using BGP to distribute MAC addresses and IP addresses of hosts across different VXLAN segments3. EVPN-VXLAN also provides benefits such as loop prevention, load balancing, mobility, and scalability3. References: 3
https://www.arubanetworks.com/assets/tg/TG_EVPN_VXLAN.pdf

The likely cause of the issue of weak Wi-Fi coverage in the office is that the AP is using a directional antenna.
A directional antenna is an antenna that radiates or receives radio waves more strongly in one or more directions, creating a focused beam of signal. A directional antenna can provide better coverage and performance for a specific area, but it can also create dead zones or weak spots for other areas. The other options are incorrect because they either do not affect the Wi-Fi coverage or do not match the scenario.
References: https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions
/wlan-rf/rf-fundamentals.htm https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content
/arubaos-solutions/wlan-rf/antennas.htm