Netlogon Event ID 5719 or Group Policy Event 1129 is logged when you start a Domain Member
I have this issue on my physical machine when NAC Agent is installed on them and sometimes, we faced with “There are currently no logon servers available to service the logon request“. The issue was happened randomly and we have to restart the machine for resolving issue.
Microsoft has published a KB and you can read the solutions for the problem:
Also a hotfix has been released for Windows 7 about DHCP relay agent delay, I suggest that installed the hotfix on your clients: