PPM LDAP error

We are in the process of implementing LDAP configuration for PPM.I have modified the required LDAP parameters in server.conf file
But i'm not able to login to PPM with my LDAP credentials.
This is the error message shown.

"Please validate the LDAP_URL parameter in the server.conf. (KNTA-10843) "

What could be the possible reason?Could anyone please help..