Under certain circumstances, such as site- or grid-wide IP address changes, one or more groups of nodes might not be able to contact the rest of the grid.
In the Grid Manager, if a node is gray, or if a node is blue with many of its services showing a status other than Running, you should check for node isolation.
To resolve the isolation issue, you run a command line utility on each node or on one node in a group that is isolated from the grid. The utility provides the nodes with the IP address of a non-isolated node in the grid, which allows the isolated node or group of nodes to contact the entire grid again.