This is the human-readable error text that accompanies the numeric remote-invocation error code for this object's state machine. When an admin creates or edits this QoS policy, UCS Manager has to push the change out to the fabric interconnects asynchronously, and this object is the FSM's top-level status record for that rollout. An example value would be something like 'Failed to configure QoS class on fabric interconnect: resource unavailable', which is far more actionable to a network admin than the bare error code alone.