TACACS is not working in 7206 VXR

Question

Hi all,
TACACS is not working in my 7206 VXR.When i am telneting in to router it is  showing Authorization Failed.I can able to login using console.
KEY is same b/w router and the server .Please help.
7206(config)#do sh run | in aaa|tacacs
aaa new-model
aaa authentication login default group tacacs+ local
aaa authentication enable default group tacacs+ enable
aaa authorization exec default group tacacs+ local if-authenticated
aaa authorization commands 15 default group tacacs+ local
aaa accounting exec default start-stop group tacacs+
aaa accounting commands 15 default start-stop group tacacs+
aaa session-id common
ip tacacs source-interface Loopback0
tacacs-server host 202.148.202.174
tacacs-server key 7 073D055B42291A413630384D2E
GURG-7206-EDGE1(config)#do ping 202.148.202.174 source lo0
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 202.148.202.174, timeout is 2 seconds:
Packet sent with a source address of 202.148.199.196
Success rate is 100 percent (5/5), round-trip min/avg/max = 40/43/44 ms

Answer 1

It is most likely a configuration or rechability issue. Double check
that you've got the right IP in the config, and that there's nothing
interfering with UDP between the two. With tacacs, it's good idea
to have known backup telnet & enable passwords, this same kind of
thing can happen when you have a badly congested link or some kind of
network problem and life is better when you can get into the router.