Facetime on mac only work after restart.

If you encounter issues making or receiving FaceTime calls, try the following:

• Verify that FaceTime is enabled in FaceTime > Preferences.

  If the issue persists, or if you see the message "Waiting for Activation", try toggling FaceTime off and then on.

• Verify that the Date, Time, and Time Zone are set correctly:
  1. From the Apple () menu, choose System Preferences > Date & Time > Date & Time.
  2. Enable "Set Automatically".
  3. Click the Time Zone tab and confirm the closest city is correct.
• Verify that both parties are connected to an active broadband Internet connection.
  • See Mac OS X: Troubleshooting a cable modem, DSL, or LAN Internet connection.
  • Consult Using FaceTime behind a firewall for necessary ports to open in firewalls, security software and routers.
  • If you encounter issues using a Wi-Fi network, use standard Wi-Fi network troubleshooting to resolve interference and other issues.
• Verify the phone number or email address being used is the correct one activated for FaceTime.

  You can verify that you are using a valid Apple ID at appleid.apple.com. You can also create an Apple ID or reset your password from this website.

• Verify that both parties have installed the latest software updates for their Mac and/or device. See:
  • Mac OS X: Updating your software
  • iOS: How to update your iPhone, iPad, or iPod touch

…none of that changed anything