This icon represents a "Deployment failure" on the clinet meaning that some component failed to install properly. You can run the SymHelp tool on the client to check for errors. If that is not helpful, you may follow the below steps to fix it.
1) Delete the concerned client's entry in SEPM. Update the policy on the SEP client. This will create a new entry for that client in SEPM. If the issue still persist go to step 2.
2) Perform a repair install of the SEP client on the affected machine. If the issue still persist go to step 3.
3) Uninstall the SEP client from the affected machine and reinstall it.