You may see following error in Cisco UCS Manager:

default Keyring’s certificate is invalid

The reason is Admin -> Key Management -> KeyRing default is expired. It’s not possible to delete or change the KeyRing in GUI. You have to log in to SSH of Cisco UCS Manager and run following commands (The strings after “#”):

lab-B# scope security
lab-B /security # scope keyring default
lab-B /security/keyring # set regenerate yes
lab-B /security/keyring* # commit-buffer
lab-B /security/keyring #

This will result in a disconnect of the Cisco UCS Manager GUI on your client computer. Just refreshing the page after 5 seconds. It’s no impact to blades.