The customer has managed client that appear to be disconnected from the Notification Server with no reason as to why.
"11/14/2014 11:26:21 AM ConfigServer AeXNSAgent.exe Configure Server Mode: Failed to obtain machine resource GUID AeXNSAgent.exe"
"11/14/2014 12:42:47 PM ConfigServer AeXNSAgent.exe Configure Server Mode: No policy key is found or policy key was changed, will reinitialize machine GUID AeXNSAgent.exe"
"11/17/2014 10:04:20 AM ConfigServer AeXNSAgent.exe Failed to find the server key: url HTTP://smp.domain.com/Altiris/NS/Agent/CreateResource.aspx AeXNSAgent.exe"
"11/17/2014 10:06:20 AM Agent AeXNSAgent.exe Failed to register agent. Registration status 'Pending'. Next retry in 4 min. AeXNSAgent.exe"
"11/14/2014 12:14:06 PM","Policy reading suspended:
Altiris.NS.Exceptions.NSComException (Altiris.Common): The specified resource is not ready: guid=204e1e5f-2803-452a-9b19-d263b418e9f4, type=493435f7-3b17-4c4c-b07f-c23e7ab7781f. This condition is temporary and will be resolved by the next collection update."
The Agent Registration policy on the NS was disabled.
Enable the Agent Registration policy (under Settings>Agents/Plug-ins>Symantec Management Agent>Settings>Registration Policies) and run a Full Membership Update.
Upon checking a few more client machines we see they are disconnected, but upon them requesting an updated configuration we see communication takes place and they are once again connected.