I’ve run into this before. This should be what you need to fix things.
First you want to determine what client (or clients) is presenting the certificate problem. Run the following SQL query against your BFEnterprise database to get a list of clients with certificate issues.
select ComputerID, ComputerName, AgentType from dbo.COMPUTERS where IsDeleted = 0 and ComputerID not in (select ComputerID from dbo.COMPUTER_CERTIFICATES)
Next you want to force the ciient to reset its ComputerID and generate a certificate by running the task named "BES Support Task #1976 “TROUBLESHOOTING: Reset the BES Client - BES >= 9.0”
Once that’s all done and things are (hopefully) working with the new client (you’ll have duplicate computers in the console after the reset) be sure to remove the old client by right-clicking on it in the console and selecting the ‘Remove From Database…’ option.