Follow these steps if you can't get past the Connecting... message when connecting to a Mac.  

You may need to enable the Mac's built-in VNC server in the Sharing preferences. To fix this follow these steps on your Mac:

1. Open up the System Preferences app on your Mac. 
2. Click the Sharing icon. 
3. Click Computer Settings in the Remote Management or Screen Sharing section.
4. Make sure VNC viewers may control screen with password is checked and set a VNC password and then press Okay.

Try connecting on your iPad / iPhone.