[sudo-users] pam_ssh_agent_auth hanging

[123 456]

on ubuntu 14.04, pam_ssh_agent_auth is hanging at the end of the debugging
output below

esadmin at bfsa1:~$ sudo su -
debug1: client_input_channel_open: ctype auth-agent at openssh.com rchan 2 win
65536 max 16384
debug2: fd 7 setting O_NONBLOCK
debug3: fd 7 is O_NONBLOCK
debug1: channel 1: new [authentication agent connection]
debug1: confirm auth-agent at openssh.com
debug2: channel 1: rcvd eof
debug2: channel 1: output open -> drain
debug2: channel 1: obuf empty
debug2: channel 1: close_write
debug2: channel 1: output drain -> closed
debug1: channel 1: FORCE input drain
debug2: channel 1: ibuf empty
debug2: channel 1: send eof
debug2: channel 1: input drain -> closed
debug2: channel 1: send close
debug3: channel 1: will not send data after close
debug3: channel 1: will not send data after close
[sudo] password for esadmin: debug3: channel 1: will not send data after
close
debug2: channel 1: rcvd close
debug3: channel 1: will not send data after close
debug2: channel 1: is dead
debug2: channel 1: garbage collecting
debug1: channel 1: free: authentication agent connection, nchannels 2
debug3: channel 1: status: The following connections are open:
  #0 client-session (t4 r0 i0/0 o0/0 fd 4/5 cc -1)
  #1 authentication agent connection (t4 r2 i3/0 o3/0 fd 7/7 cc -1)

esadmin at bfsa1:~$ env | grep SSH
SSH_CLIENT=10.42.66.241 5729 22
SSH_TTY=/dev/pts/1
SSH_AUTH_SOCK=/tmp/ssh-KaU3jIQPQn/agent.4045
SSH_CONNECTION=10.42.66.241 5729 10.43.6.50 22


auth       required   pam_env.so readenv=1 user_readenv=0
auth       required   pam_env.so readenv=1 envfile=/etc/default/locale
user_readenv=0
auth       sufficent  pam_ssh_agent_auth.so file=%h/.ssh/authorized_keys
debug
@include common-auth
@include common-account
@include common-session-noninteractive

no change to sudo config

can ssh from a->b->c
can not sudo on b

any ideas?