The NLB node is converging frequently. While the cluster is converging clients may experience connectivity problems to the load balanced application. This could be indicative of a problem with a network device connecting the NLB nodes.
The frequent convergence can occur due to the following reasons:
A bad network adapter, cable or switch port may be preventing reliable heartbeat communication between NLB hosts.
Mismatched duplex settings on the network adapter and switch may be causing unreliable heartbeat communication.
The switch, network adapter or protocol stack is dropping packets due to insufficient resources.
To check for occurrences of configuration problems with NLB, you can use the Active Alerts view. It is also recommended to consult the network adapter and network device documentation.