I can only work from the information that you have provided.
The error message you posted very clearly has the server as 127.0.0.1 which is the local machine that elasticsearch is running on.
If that is the error message you are seeing, then it indicates that your DNS resolver thinks "domainexample.com" is on the local machine. And that's not a elasticsearch issue.
If that's not the real error message, then you're going to have to work out whether the IP address that is in your message is in fact the IP of your Active Directory server. Because as far as Elasticsearch can tell, there is nothing listening on port 389 of that server. It could be that you have the wrong domain name. It could be that you have a DNS issue. It could be that you have a firewall or other network device preventing access. All of those are issues that you will have to check for yourself.