rlm_ldap (ldap): Failed setting connection option new TLS context: Unknown error

[Shem Pasamba]

Hello,

I have a problem connecting to an ldaps:// server using freeradius-ldap in
Ubuntu 18.04, it says, when I run freeradius -X -xxx:
Tue Oct 15 16:47:55 2019 : Debug: rlm_ldap (ldap): Connecting to ldaps://
ldap.aiias.edu:636
Tue Oct 15 16:47:55 2019 : Debug: rlm_ldap (ldap): New libldap handle
0x564a538dda60
Tue Oct 15 16:47:55 2019 : Error: rlm_ldap (ldap): Failed setting
connection option new TLS context: Unknown error

Here's what I did:
Installed freeradius using 'apt-get install freeradius-ldap'
then modified /etc/freeradius/3.0/mods-available/ldap to have:
        server = 'ldaps://ldap.aiias.edu'
        port = 636
        identity = 'cn=Administrator,cn=users,dc=aiias,dc=edu'
        password = not-the-real-password
        base_dn = 'dc=aiias,dc=edu'

        tls {
                certificate_file = ${certdir}/aiias-edu.crt
                private_key_file = ${certdir}/aiias-edu.key
        }
then linked mods-available/ldap to ../mods-enabled/ldap

Thanks for your help in advance.

All the best,

Shem Pasamba