PAM3.6: SSH-Relay asking for passphrase???

Hi Everyone,

In PAM 3.6 I have configured SSH-Relay rule along with root user password but when going to access SSH-Relay, it prompting to enter passphrase of private key, why?

screen shot of rule:

screen shot of the vault:

screen shot of problem:

I don't understand if I have configured in credential type to use password then why its asking to enter passphrase?