It looks like after you have pushed the client packages, the installation of SEP did not go through completely (there might be a pending restart) or there is a communication failure between SEP and SEPM. Can you verify this by opening the SEP UI (double-click the SEP UI tray icon) and checking the Troubleshooting option in the Help. My guess is that in General information you might be seeing 'Self-Managed' or 'Offline'.
Manually adding client names will not work because your SEP is not able to communicate with SEPM. And so all clients are showing offline.
What you will need to do is export the communication settings from SEPM. There is a link on SEPM Clients tab -> Policies to 'Export Communications Settings'. Take the exported sylink.xml and manually import it in the SEP using 'Import' button on the troubleshooting page in SEP UI. Wait for 5-10 seconds and reopen the SEP UI. Troubleshooting page on SEP UI should show the name of the SEPM server.
Please delete the manual entry you have added before these steps.