Problem setting 7606 router for TACACS+ authentication

Question

Hello Support Community,
I have two Cisco 7606 routers which I have tried in vain to have users authenticated using TACACS+ servers. As shown below, I have two servers (1.1.1.1 and 2.2.2.2) reachable via vrf OAM which is reachable from desktops for ssh login. The true IP addresses and vrf have been altered because it's a company router.
I use the two servers to authenticate many other Cisco devices in the network they are working fine.
I can reach the servers from the vrf and the source interface in use. I can also telnet port 49 if the servers from the source interface and the vrf.
The server key is hidden but at the time of configuration, I can ascertain that it's correct.
The problem is that after confuring for TACACS authentication, the router still uses the enable password instead of TACACS. While the debug output shows 'bad password', why is the router not authenticating using TACACS? Why is it using the enable password?
Please study the outputs below and help point out what I may need to change.
PS: I have tried out many other combinations, including deprecated ones without success including the method suggested in this page;
http://www.cisco.com/en/US/docs/ios/sec_user_services/configuration/guide/sec_vrf_tacas_svrs.html
Please help I'm stuck.
ROUTER#sh running-config | sec aaa
aaa new-model
aaa group server tacacs+ admin
server name admin
server name admin1
ip vrf forwarding OAM
ip tacacs source-interface GigabitEthernet1
aaa authentication login admin group tacacs+ local enable
aaa session-id common
ROUTER#sh running-config | sec tacacs
aaa group server tacacs+ admin
server name admin
server name admin1
ip vrf forwarding OAM
ip tacacs source-interface GigabitEthernet1
aaa authentication login admin group tacacs+ local enable
tacacs server admin
address ipv4 1.1.1.1
key 7 XXXXXXXXXXXXXXXXXXXX
tacacs server admin1
address ipv4 2.2.2.2
key 7 XXXXXXXXXXXXXXXXxxxx
line vty 0 4
login authentication admin
ROUTER#sh tacacs
Tacacs+ Server -  public  :
               Server name: admin
            Server address: 1.1.1.1
               Server port: 49
              Socket opens:         15
             Socket closes:         15
             Socket aborts:          0
             Socket errors:          0
           Socket Timeouts:          0
   Failed Connect Attempts:          0
        Total Packets Sent:          0
        Total Packets Recv:          0
Tacacs+ Server -  public  :
               Server name: admin1
            Server address: 2.2.2.2
               Server port: 49
              Socket opens:         15
             Socket closes:         15
             Socket aborts:          0
             Socket errors:          0
           Socket Timeouts:          0
   Failed Connect Attempts:          0
        Total Packets Sent:          0
        Total Packets Recv:          0
Oct 22 12:38:57.587: AAA/BIND(0000001A): Bind i/f 
Oct 22 12:38:57.587: AAA/AUTHEN/LOGIN (0000001A): Pick method list 'admin'
Oct 22 12:38:57.587: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:38:57.587: AAA/AUTHEN/ENABLE(0000001A): Done status GET_PASSWORD
Oct 22 12:39:02.327: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:39:02.327: AAA/AUTHEN/ENABLE(0000001A): Done status FAIL - bad password
Oct 22 12:39:04.335: AAA/AUTHEN/LOGIN (0000001A): Pick method list 'admin'
Oct 22 12:39:04.335: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:39:04.335: AAA/AUTHEN/ENABLE(0000001A): Done status GET_PASSWORD
Oct 22 12:39:08.675: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:39:08.675: AAA/AUTHEN/ENABLE(0000001A): Done status FAIL - bad password
Oct 22 12:39:10.679: AAA/AUTHEN/LOGIN (0000001A): Pick method list 'admin'
Oct 22 12:39:10.683: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:39:10.683: AAA/AUTHEN/ENABLE(0000001A): Done status GET_PASSWORD
Oct 22 12:39:14.907: AAA/AUTHEN/ENABLE(0000001A): Processing request action LOGIN
Oct 22 12:39:14.907: AAA/AUTHEN/ENABLE(0000001A): Done status FAIL - bad password
ROUTER#sh ver
Cisco IOS Software, c7600rsp72043_rp Software (c7600rsp72043_rp-ADVIPSERVICESK9-M), Version 15.1(3)S3, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2012 by Cisco Systems, Inc.
Compiled Fri 30-Mar-12 08:34 by prod_rel_team
ROM: System Bootstrap, Version 12.2(33r)SRE, RELEASE SOFTWARE (fc1)
BOOTLDR: Cisco IOS Software, c7600rsp72043_rp Software (c7600rsp72043_rp-ADVIPSERVICESK9-M), Version 15.1(3)S3, RELEASE SOFTWARE (fc1)
ROUTER uptime is 7 weeks, 5 days, 16 hours, 48 minutes
Uptime for this control processor is 7 weeks, 5 days, 16 hours, 49 minutes
System returned to ROM by reload (SP by reload)
System restarted at 20:00:59 UTC Wed Aug 28 2013
System image file is "sup-bootdisk:c7600rsp72043-advipservicesk9-mz.151-3.S3.bin"
Last reload type: Normal Reload
Last reload reason: power-on
This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html
If you require further assistance please contact us by sending email to
[email protected].
Cisco CISCO7606-S (M8500) processor (revision 1.1) with 3670016K/262144K bytes of memory.
Processor board ID FOX1623G61B
BASEBOARD: RSP720
CPU: MPC8548_E, Version: 2.1, (0x80390021)
CORE: E500, Version: 2.2, (0x80210022)
CPU:1200MHz, CCB:400MHz, DDR:200MHz,
L1:    D-cache 32 kB enabled
        I-cache 32 kB enabled
Last reset from power-on
3 Virtual Ethernet interfaces
76 Gigabit Ethernet interfaces
8 Ten Gigabit Ethernet interfaces
3964K bytes of non-volatile configuration memory.
500472K bytes of Internal ATA PCMCIA card (Sector size 512 bytes).
Configuration register is 0x2102

Answer 1

In order to resolve this issue. Please replace the below listed command
aaa authentication login admin group tacacs+ local enable
with;
aaa authentication login default group admin local enable
You defined the server group name as method list and instead of using admin as a server-group, you used tacacs+
Note: Please ensure you have local user and enable password configured in case of tacacs server unreachable.
~BR
Jatin Katyal
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