A network administrator has configured TACACS on a network device using the key Cisc0466974274 for authentication purposes. However, users are unable to authenticate. TACACS server is reachable, but…

For TACACS+ authentication to succeed, the shared secret key configured on the network device must precisely match the key configured on the TACACS server. This key is crucial for encrypting communication and verifying the authenticity of both the client and server, and any mismatch will result in authentication failures.

While operating system compatibility is important, an incorrect shared secret key is a more direct and common cause of TACACS+ authentication failure when the server is reachable.

Synchronized system clocks are vital for certain authentication protocols like Kerberos but are not the primary cause of TACACS+ authentication failure specifically due to a key mismatch.

If the TACACS server is reachable, it implies that basic network connectivity and necessary access control lists allowing communication are likely already configured or not the root cause of the authentication failure.