Downgrade from Yosemite OS to Mavericks OS: -2003F message error Please I wanna ask you if you can help me to resolve this issue.

I have make a handling to downgrade from Yosemite OS to Mavericks OS.
After this, my Mac cannot start up, it displays a folder with question mark
I've tried to boot with (cmd + R) but I got this strange error "-2003F"
Try to boot in Safe Mode (Cmd+x) to see if it boots. If not, try to boot in single user mode (Cmd+s) and have a look at the output on the screen. It may be able to give you more information to help you solve this issue or post screenshots here.