Edit: After half day, my wife’s Mac started having the same problem. I have then applied the solution that I found in the Apple
iOS 7 to Launch with FaceTime Audio Only
So much was announced today during Apple’s WWDC. We saw a new Mac Pro, MacBook Air, and new operating updates for Mac and iOS. iOS 7 was announced was branded as the “biggest change” to iOS since the introduction of the original iPhone.
Well if you are a fan of FaceTime it just got better. iOS 7 will launch with FaceTime Audio. It is service that is set to replace you phone calls. Currently FaceTime is an Apple video-calling service. It is now expended to cover audio only to help during those situations with poor video quality.
FaceTime Audio will allow users to call other Apple users for free. This is great news for those that have poor coverage who look to still use voice calls over Wi-Fi. The details ensures that FaceTime will also work over your data network connection which means you should be able to use FaceTime Audio over Wi-Fi, 3G/4G, and LTE connections.
This is a nice additional feature Apple has added to FaceTime. Unfortunately we have to wait until Fall 2013 to be able to utilize this new feature. Apple has announced that iOS 7 will become available to the public in the Fall 2013 while developers will get a preview starting today.