Problems with F5 Rseries and LDAPs for remote authentication

Good afternoon

I'm having some problems getting remote authentication to work on my Rseries computer over LDAPS, when debugging I get the following error:

Can't contact LDAP server: error:14090086:SSL routines:ssl3_get_server_certificate:certificate verify failed (unable to get local issuer certificate)

I have followed several guides and consulted different articles, but I can't find any of them which fields are mandatory and which aren't. My question is regarding the fields: Cipher String, TLS CA Certificate and TLS Key. Is it mandatory to fill in these fields? What happens if they are left empty?

Best Regards