Aruba's Captive Portal uses Layer 3 authentication, which means that it intercepts the client's HTTP requests and redirects them to a web page where the client can enter their credentials. The credentials are then verified by a RADIUS server or a local database before granting network access.
References: https://www.arubanetworks.com/techdocs/Instant_86_WebHelp/Content/instant-ug/captive- portal/ca

A UXI (User Experience Insight) is a device that simulates user behavior and tests network performance from the user perspective. It can check different applications, such as HTTP, VOIP, or Office 365, and measure metrics such as latency, jitter, packet loss, and throughput.References:https://www.arubanetworks.com
/products/networking/user-experience-insight/
A User Experience Insight (UXI) sensor, such as those used in Aruba networks, is designed to mimic client behavior and test the performance of various network services and applications from the user's perspective. It can simulate user activities and measure the quality of experience for different applications, including HTTP, VOIP, and cloud services like Office 365, providing valuable insights into network performance and user experience.

The way that STP Spanning Tree Protocol. STP is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network by preventing redundant paths between switches or bridges from creating loops that cause broadcast storms, multiple frame transmission, and MAC table instability. STP creates a logical tree structure that spans all of the switches in an extended network and blocks any redundant links that are not part of the tree from forwarding data packets3. will forward or discard traffic on these ports is as follows:
* STP will elect a root bridge among the two switches based on their bridge IDs, which are composed of a priority value and a MAC address. The switch with the lower bridge ID will become the root bridge and will forward traffic on all its ports.
* STP will assign a role and a state to each port on both switches based on their port IDs, which are composed of a priority value and a port number. The port with the lower port ID will become the designated port and will forward traffic, while the port with the higher port ID will become the alternate port and will discard traffic.
* In this scenario, since both switches have two cables connected between ports 1/1/1 and 1/1/2, there will be two possible paths between them, creating a loop. To prevent this loop, STP will block one of these paths by discarding traffic on one of the ports on each switch.
* Assuming that both switches have the same priority value (default is 32768), the switch with the lower MAC address will have the lower bridge ID and will become the root bridge. The root bridge will forward traffic on both ports 1/1/1 and 1/1/2.
* Assuming that both ports have the same priority value (default is 128), port 1/1/1 will have a lower port ID than port 1/1/2 on both switches because it has a lower port number. Port 1/1/1 will become the designated port and will forward traffic, while port 1/1/2 will become the alternate port and will discard traffic.
* Therefore, the switch with the lower MAC address will discard traffic on one port (port 1/1/2), while the switch with the higher MAC address will also discard traffic on one port (port 1/1/2).
References: 3 https://en.wikipedia.org/wiki/Spanning_Tree_Protocol

Explanation
Layer 2 MAC authentication is a method of authenticating devices based on their MAC addresses without requiring any client-side configuration or credentials. The switch sends the MAC address of the device to an authentication server such as ClearPass or RADIUS, which checks if the MAC address is authorized to access the network. If yes, the switch grants access to the device based on the assigned role and policies. If no, the switch denies access or redirects the device to a captive portal for further authentication.
References:https://www.arubanetworks.com/techdocs/ArubaOS_86_Web_Help/Content/arubaos-solutions/1-ove

Explanation
These commands might help troubleshoot this issue as they check various aspects of the connectivity between the edge switch and the core switch, such as Layer 3 reachability, Layer 2 adjacency, LACP configuration and status, VLAN trunking configuration, and interface status.
References:https://www.arubanetworks.com/techdocs/AOS-CX_10_04/CLI/GUID-8F0E7E8B-0F4B-4A3C-AE7