First of all, please make sure you have the necessary settings enabled.

Here is how you do it:

  1. Connect the device with a USB cable.
  2. Locate it within iTunes.
  3. Go to Summary.
  4. Click Options → to enable the checkbox “Sync with this device over WiFi”.

If the issue persists...

  1. Please go to iTunes, disable WiFi connectivity for the device, enable it back, and hit 'Apply’.
  2. Restart both the computer and the device.
  3. Try connecting via WiFi afresh.

In case that didn't help...

Check if the device can be seen over WiFi in iTunes.

IF YES please reinstall SYC 2.
IF NO please reinstall iTunes, then SYC 2.

Good luck!