I was looking into a case for one of very high profile customer where their CIMC (Cisco Integrated Management Controller) was showing PS Redundancy status as ‘lost’. However, both PSU were up and Normal. Have a look at the screenshot below:
By searching through Bug Tool kit I found two bugs for this particular issue – CSCtx66554 & CSCtt03265 which is affecting C200/210 series and there is no fix as of yet.
Have a look at the workaround and it may fix the issue but if not then you can Order a replacement from Cisco.
There is a Field replacement notice as well which you can find at http://www.cisco.com/en/US/ts/fn/634/fn63425.html