I'm completely at a loss for what to try at this point. I've gone through about every step I can find with Google, with no luck. I have a new Macbook Pro running El Capitan (10.11.6). I am able to ping either of our domain controllers. In network settings, I can confirm that it has a proper IP address, our domain (company.local, for this purpose) is shown in Search Domains, and the proper DNS servers are listed. Whenever I try to join the domain, I am greeted with a message that is it unable to contact the directory server. Sometimes, it adds a 5200 at the end of the message. I am using domain admin credentials, and have tried creating the computer account in AD already and without the account being present. Is there anything else I can try? The two domain controllers are both running Server 2016, if that matters.