Keys not found (PGP Messaging) - Symantec Encryption Server

We are currently configuring the Symantec Encryption Desktop for Messaging. I have managed clients using SKM. However, if I send encrypted email internally. There's always an error keys not found: Blocked Message. I'm not sure if I missed some configuration here.

- LDAP Settings is successful.

- SKM

- Mail Policy default

- Enable Messaging on Desktop policy

If I try to search keys from my pgp desktop using the Encryption Server. Result is : No Keys Found.

Help please..

thanks,