Recently, I found a lot of NETLOGON warnings in the system log. As I know my network is very clean, I was very curious about this. Every anomaly in my network requires careful examination.
After analysis of the log file, I found the root cause of this warning. Over time, we added some servers in the test network and at the same time added them to the AD domain. However, I omitted to define this subnet range in the AD site structure.