RPC Server unavailable. 0x800706BA

I've alsready seen some similar threads on the RPC server unavailable messages; HRESULT: 0x800706BA. I've read some and looked at the recommendations on this thread;

WMI query between two different AD sites?

While there were some helpful hints it doesnt quite fit my questions...

I'm using an endpoint security platform and am trying to oush\update policys to endpoints within the network. I'm seeing differing results when i try to push or amend polices from the managment console (virtual server).

On random machines I get the RPC Server unavailable messge HRESULT: 0x800706BA returned. yet on others the policy updates almost instantly. Initaaly I suspected that this was a firewall\GPO ('ve added addtional rules to allow for WMI\RPC traffic in both directions) issue, however given that many machines can update would seem to rule this out, indeed I have machinwe which is fully connected to the network, has not had any issues with policy updates in the past, now returing the RPC error message.

I'm now at at an impasse. And would appreicate any help woth this issue.

Kind regards.

RobW.