SG FLX needs tls entries to be defined in an LDAP IDP to use it, as it shown at LDAPConnectionManager.java. But the JVM can be correctly configured, and there is no settings to change if the needed certificates are present in the default key store. The use of ldaps scheme in the LDAP URL should be enough. I needed to configure my IDP as the following fragment to make it work:
idp:
hosts:
- "ldaps://XXXX:636"
- "ldaps://XXXX:636"
- "ldaps://XXXX:636"
bind_dn: "XXXX"
password: "XXXX"
tls:
enabled_protocols:
- "TLSv1.2"
- "TLSv1.3"
trust_all: false
Without the tls entry, it was using ldap, not ldaps