Two errors on Exchange 2010 server

I am running Exchange 2010 Version 14.1 (Build 218.15) on Windows Server 2008R2 Enterprise SP1 Build 7601.  I am getting the following error.

Error: Microsoft.Exchange.Cluster.Replay.AmClusterApiException: An Active Manager operation failed. Error: An error occurred while attempting a cluster operation. Error: Cluster API '"OpenCluster(Exchange02.mydomain.com) failed with 0x6d9. Error: There are no more endpoints available from the endpoint mapper"' failed.. ---> System.ComponentModel.Win32Exception: There are no more endpoints available from the endpoint mapper

I dont know what called that Cluster API - if I were to guess it would be either Veeam or VMware (snapshot) during the backup process but I dont know.  

The second error from the log is:

The Cluster service is shutting down because quorum was lost. This could be due to the loss of network connectivity between some or all nodes in the cluster, or a failover of the witness disk. Run the Validate a Configuration wizard to check your network configuration. If the condition persists, check for hardware or software errors related to the network adapter. Also check for failures in any other network components to which the node is connected such as hubs, switches, or bridges.

I checked and network connectivity is ok.

Does anyone know to where to begin with this?
Replication.PNG
FailoverClustering.PNG