No communication between the switch and the TACACS+ server application

If the switch can access the server device (that is, it can ping the server), a configuration error may be the problem. Some possibilities include:

• The server IP address configured with the switch's tacacs-serverhost command may not be correct. (Use the switch's show tacacs-server command to list the TACACS+ server IP address.)

• The encryption key configured in the server does not match the encryption key configured in the switch (by using the tacacs-server key command). Verify the key in the server and compare it to the key configured in the switch. (Use show tacacs-server to list the global key. Use show config or show config running to list any server-specific keys.)

• The accessible TACACS+ servers are not configured to provide service to the switch.