Failed to connect Freeradius to OpenLDAP

[Tsirkas Georgios]

Hello,

I am trying to use ldap module. But failed to connect....

With SSL
//

/Wed Apr 25 13:47:07 2018 : Info: rlm_ldap (ldap): Opening additional 
connection (0), 1 of 32 pending slots used//
//Wed Apr 25 13:47:07 2018 : Debug: rlm_ldap (ldap): Connecting to 
ldap://ldap-server:636//
//Wed Apr 25 13:47:07 2018 : Debug: rlm_ldap (ldap): New libldap handle 
0x55de89593c20//
//TLS: can't connect: (unknown error code).//
//Wed Apr 25 13:47:08 2018 : Error: rlm_ldap (ldap): Bind with 
cn=admin,dc=mydomain,dc=gr to ldap://ldap-server:636 failed: Can't 
contact LDAP server//
//Wed Apr 25 13:47:08 2018 : Debug: rlm_ldap: Closing libldap handle 
0x55de89593c20//
//Wed Apr 25 13:47:08 2018 : Error: rlm_ldap (ldap): Opening connection 
failed (0)//
//Wed Apr 25 13:47:08 2018 : Debug: rlm_ldap (ldap): Removing connection 
pool//
//Wed Apr 25 13:47:08 2018 : Error: 
/etc/freeradius/3.0/mods-enabled/ldap[8]: Instantiation failed for 
module "ldap"/

Without SSL

Wed Apr 25 13:51:52 2018 : Info: rlm_ldap (ldap): Opening additional 
connection (0), 1 of 32 pending slots used
Wed Apr 25 13:51:52 2018 : Debug: rlm_ldap (ldap): Connecting to 
ldap://ldap-server:389
Wed Apr 25 13:51:52 2018 : Debug: rlm_ldap (ldap): New libldap handle 
0x55f00a1e4c20
Wed Apr 25 13:51:52 2018 : Error: rlm_ldap (ldap): Bind with 
cn=admin,dc=mydomain,dc=gr to ldap://ldap-server:389 failed: Can't 
contact LDAP server
Wed Apr 25 13:51:52 2018 : Debug: rlm_ldap: Closing libldap handle 
0x55f00a1e4c20
Wed Apr 25 13:51:52 2018 : Error: rlm_ldap (ldap): Opening connection 
failed (0)
Wed Apr 25 13:51:52 2018 : Debug: rlm_ldap (ldap): Removing connection pool
Wed Apr 25 13:51:52 2018 : Error: 
/etc/freeradius/3.0/mods-enabled/ldap[8]: Instantiation failed for 
module "ldap"

Any ideas? I am using Freeradius 3.0.12 with Debian....