Howard,
It appears the primary FI is not responding to the command.
Is your HA state healthy? If you want a quick fix, you may choose to reload the FIs one at a time or restart the processes on the primary FI. Make sure this is done in a maintenance window.
What version of UCSM are you running? Can you share the following outputs from FI-A and FI-B.
'show cluster extended-state'
'Connect local-mgmt'
'show pmon state'
This is a related defect:
https://tools.cisco.com/bugsearch/bug/CSCul61847/?reffering_site=dumpcr
HTH,
Wes