Novell Ldap: missing LdapSearchResult message type in the LdapSearchQueue followint Search

I want to first say that unfortunately I am unable to change the code in this specific scenario, and that the code works everywhere except for this one installation. I suspect a configuration/permissions/trust issue, and I am hoping to get advice on how to modify the environment to fix this.

In this specific place, After running Search() method on LdapConnection, I get an LdapSearchQueue that does not contain LdapSearchResult for some reason. Note that LdapSearchQueue does contain other messages (specifically LdapSearchResultReference and LdapResponse), just not the LdapSearchResult. I can manually examine the AD and see that theoretically it should have the correct response.

Obviously it ends up with entry being null.

var filter = $"(&(objectClass=User)(sAMAccountName={<user_name>}))";
var searchBase = "DC=<domain_name>,DC=com";
var search = conn.Search(searchBase, LdapConnection.SCOPE_SUB, filter, null, false, null, null);
    LdapMessage message;
    LdapEntry entry = null;
    while ((message = search.getResponse()) != null)
    {
         if (!(message is LdapSearchResult searchResultMessage))
         {
              continue;
         }
         entry = searchResultMessage.Entry;
    }

Any advise is appreciated