The network adapter to which Network Load Balancing (NLB) is bound must be properly configured and capable of performing NLB operations. If the adapter is not properly configured, the NLB driver may fail to bind to the adapter.
Disable and re-enable NLB network adapters
When the Network Load Balancing (NLB) driver fails to attach to the network adapter or fails to register with the Network Driver Interface Specification (NDIS), the host will not be an active member of the NLB cluster. You should disable and re-enable the network adapter before attempting to bind NLB to the adapter again.
To disable and re-enable all network adapters:
Open Network and Sharing Center, and then click Manage network connections.
Right-click the network adapter you want to disable, and click Disable. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
Right-click the network adapter you want to enable, and click Enable. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.