I found this on the Apple support page
If you can't start up from macOS Recovery
Newer Mac computers and some older Mac computers automatically try to start up from macOS Recovery over the Internet when unable to start up from the built-in recovery system. When that happens, you see a spinning globe instead of an Apple logo during startup. To manually start up from macOS Recovery over the Internet, press and hold Option-Command-R or Shift-Option-Command-R at startup. Learn more about these key combinations.
If you still can't start up from macOS Recovery, you might need to reinstall macOS after starting up from another disk or volume, or by using a bootable installer.
macOS Recovery over the Internet, the Reinstall macOS utility, and the Get Help Online utility all require an Internet connection. If you need to connect to a Wi-Fi network, move your pointer to the top of the screen, then choose a network from the Wi-Fi menu in the menu bar.
Published Date: October 12, 2018