An administrator is configuring RADIUS on a Cisco switch with a key set to Cisc403012128 but is receiving the error "Authentication failed: 22040 Wrong password or invalid shared secret.". What must…

The question implies the administrator is configuring RADIUS, which includes setting up the Network Access Device (NAD) on ISE. The error points specifically to the key's value, not the absence of the NAD configuration.

The RADIUS shared secret must be configured identically on *both* the Cisco switch (client) and Cisco ISE (server) to establish secure communication. Configuring it only on one device would prevent authentication.

While strong password policies recommend longer and more complex keys, the error message indicates a mismatch or invalidity of the *current* key, not a failure due to length constraints. RADIUS shared secrets do not inherently have an 8-10 character requirement, though strong practices dictate longer, more complex secrets.

The shared secret is a pre-shared key used for securing communication between the RADIUS client (Cisco switch) and the RADIUS server (Cisco ISE). If this key is not identical on both devices, RADIUS authentication packets cannot be correctly encrypted or decrypted, leading directly to the 'Wrong password or invalid shared secret' error and preventing successful communication.