Dubarnik

When I click update I get this: CCleaner could not be updated. 0x2efd: A connection with the server could not be established. The third line gives me blue buttons to Purchase, Register, Cancel. I re-registered using the emailed information from Piriform but still get the message. I cleaned my computer, uninstalled CCleaner, reinstalled Pro but still get the message. I have a Windows 10 machine. Help, please.