Fixed it myself!
Everything works now fine! The error does not show anymore and AD is properly read!
The problem wasn't on the McAfee side, but on the server side.
If you need more details, ask!
Have a good day you all!
so, what was the problem? If you can tell us here, others can learn from it.
The problem was hiding in Network Connections settings.
I have a separate DNS server and DC server, so in Network Connections by default as Primary DNS server I entered DNS servers IP, but to fix the issue I entered DC (AD) servers IP into secondary DNS servers field.
Hope this helps someone!