ssh-add doesn't resolve "Agent admitted failure to sign using the key."
 

I'm setting up some VMs on my laptop and I want to establish passwordless ssh from local machine to VM. The process I followed was:

- ssh-keygen (all default values)
- ssh-copy-id root@VM -- confirmed key existed in node:~/.ssh/authorized_keys
- ssh root@VM
returns:
Agent admitted failure to sign using the key.
root@VM's password:

So I tried `ssh-add`, it asks for passphrase; there is none. Hit enter and it returns to prompt. ssh root@VM again just repeats the same "Agent admitted..."

Digging around the web, ssh-add has been the solution for everyone with this problem except for me. What can I do next?

Here is verbose output of ssh root@node:

[jcope@jcope ~]$ ssh root@VM -v
OpenSSH_5.3p1, OpenSSL 1.0.0-fips 29 Mar 2010
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: Applying options for *
debug1: Connecting to VM [172.16.108.128] port 22.
debug1: Connection established.
debug1: identity file /home/jcope/.ssh/identity type -1
debug1: identity file /home/jcope/.ssh/identity-cert type -1
debug1: identity file /home/jcope/.ssh/id_rsa type 1
debug1: identity file /home/jcope/.ssh/id_rsa-cert type -1
debug1: identity file /home/jcope/.ssh/id_dsa type -1
debug1: identity file /home/jcope/.ssh/id_dsa-cert type -1
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.3
debug1: match: OpenSSH_5.3 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.3
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 none
debug1: kex: client->server aes128-ctr hmac-md5 none
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
debug1: SSH2_MSG_KEX_DH_GEX_INIT sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_REPLY
debug1: Host 'VM' is known and matches the RSA host key.
debug1: Found key in /home/jcope/.ssh/known_hosts:21
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: gssapi-keyex
debug1: No valid Key exchange context
debug1: Next authentication method: gssapi-with-mic
debug1: Unspecified GSS failure. Minor code may provide more information
Invalid argument

debug1: Unspecified GSS failure. Minor code may provide more information
Invalid argument

debug1: Unspecified GSS failure. Minor code may provide more information


debug1: Authentications that can continue: publickey,gssapi-keyex,gssapi-with-mic,password
debug1: Next authentication method: publickey
debug1: Offering public key: /home/jcope/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 277
Agent admitted failure to sign using the key.
debug1: Trying private key: /home/jcope/.ssh/identity
debug1: Trying private key: /home/jcope/.ssh/id_dsa
debug1: Next authentication method: password
root@VM's password:

The client has to have used ssh-add to register the key with the ssh-agent