You can try powering down the SPb and powering it back up and seeing if it comes back up. Are you sure that nothing else was assigned the IP address of SPB? If there was an IP conflict that would probably show as the SP being unmanaged.
If the FLARE code is actually gone from the system (which isn’t take likely) then you’ll probably need to contact DELL or EMC and engage them to come and repair the problem.
The problem might be related to a vault drive failure. Vault drives are the first 5 drives in the array.