SBS 2011 stops responding

Question

Two days in a row now one of my clients has come into the office to find that their SBS2011 is no longer responding to requests, and logon times take between 15 and 30 minutes before reaching a usable desktop. The SBS2011 server is a guest VM on a Windows
2008 Hyper-V (Core) server. Both days when I connect to console via Hyper-V the server will not respond to a CTRL+ALT+DEL request. Restarting the server resolves the problem, however I cannot really determine a Root Cause. Yesterday, I just rebooted
the server and everything was fine, and I found a few messages in the application log that suggested that Exchange was having issues processing spam before sending the NETLOGON service in a tailspin, or so I thought.
Since I noticed the same thing this morning I decided to do a little troubleshooting before Turning Off the VM to restart the server.  I was able to connect to services and to event viewer, but I still don't see anything in the logs other than various
services reporting that All Domain Controller Servers in use are not responding. There are some Warnings in the System Event Log that indicate the DNS for the domain is failing registrations, but no messages as to the exact cause.
Log Name:      System
Source:        Microsoft-Windows-DNS-Client
Date:          1/27/2015 7:19:07 PM
Event ID:      1014
Task Category: None
Level:         Warning
Keywords:     
User:          SYSTEM
Computer:      SBSERVER.twi.local
Description:
Name resolution for the name twi.local timed out after none of the configured DNS servers responded.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-DNS-Client" Guid="{1C95126E-7EEA-49A9-A3FE-A378B03DDB4D}" />
    <EventID>1014</EventID>
    <Version>0</Version>
    <Level>3</Level>
    <Task>0</Task>
    <Opcode>0</Opcode>
    <Keywords>0x4000000000000000</Keywords>
    <TimeCreated SystemTime="2015-01-28T03:19:07.507526300Z" />
    <EventRecordID>1311467</EventRecordID>
    <Correlation />
    <Execution ProcessID="748" ThreadID="36044" />
    <Channel>System</Channel>
    <Computer>SBSERVER.twi.local</Computer>
    <Security UserID="S-1-5-18" />
  </System>
  <EventData>
    <Data Name="QueryName">twi.local</Data>
    <Data Name="AddressLength">16</Data>
    <Data Name="Address">02000035C0A847020000000000000000</Data>
  </EventData>
</Event>
Log Name:      System
Source:        NETLOGON
Date:          1/27/2015 7:19:42 PM
Event ID:      5781
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      SBSERVER.twi.local
Description:
Dynamic registration or deletion of one or more DNS records associated with DNS domain 'twi.local.' failed.  These records are used by other computers to locate this server as a domain controller (if the specified domain is an Active Directory domain)
or as an LDAP server (if the specified domain is an application partition). 
Possible causes of failure include: 
- TCP/IP properties of the network connections of this computer contain wrong IP address(es) of the preferred and alternate DNS servers
- Specified preferred and alternate DNS servers are not running
- DNS server(s) primary for the records to be registered is not running
- Preferred or alternate DNS servers are configured with wrong root hints
- Parent DNS zone contains incorrect delegation to the child zone authoritative for the DNS records that failed registration 
USER ACTION 
Fix possible misconfiguration(s) specified above and initiate registration or deletion of the DNS records by running 'nltest.exe /dsregdns' from the command prompt on the domain controller or by restarting Net Logon service on the domain controller.
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="NETLOGON" />
    <EventID Qualifiers="0">5781</EventID>
    <Level>3</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-01-28T03:19:42.000000000Z" />
    <EventRecordID>1311468</EventRecordID>
    <Channel>System</Channel>
    <Computer>SBSERVER.twi.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data>twi.local.</Data>
    <Binary>B4050000</Binary>
  </EventData>
</Event>
Any Ideas on where to look for possible causes and how to keep this from happening every night?
Regards, Jim Majorowicz, MCP Sr. Network Engineer Whitsell Computer Services [phone]x12 www.whitsell.com We can support you no matter where you are. Ask me for details.

Answer 1

How are the VM's configured ? I am sure they are up to the standard requirement that suits SBS architecture.
Make sure SBS has only one NIC enabled with IPv4 and IPv6 active. The issue that you are facing might be due to many reason (DNS + Exchange)
Also , please note to unmounts any USB from the Server as a Test and boot the server.
SBS on VM Configuration :
http://tutorial.programming4.us/windows_server/Configuring-Small-Business-Server-2011-in-Hyper-V---Creating-a-Virtual-Machine-(part-2)---Machine-Settings.aspx
Common Issue:
http://blogs.technet.com/b/sbs/archive/2011/02/18/small-business-server-2011-slow-to-boot-and-several-services-fail-to-start.aspx
Please make sure the steps suggested by Larry is also followed.
Binu Kumar - MCP, MCITP, MCTS , MBA - IT , Director Aarbin Technology Pvt Ltd - Please remember to mark the replies as answers if they help and unmark them if they provide no help.