Hi, I'd suggest you download the client manually & import it into your management server from a local machine.
Download the latest client from the Endpoint Security Homepage Endpoint Security Homepage (checkpoint.com) (sk117536), unpack the .zip archive and open the same window you're in right now on SmartEndpoint.
Instead of downloading the client as you are now, select "Load a folder containing client installers" and select the unpacked directory on your hard drive.
This will upload and verify the clients and you'll be able to deploy them freely as you were up until now.