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 Beta 3 Reportedly Coming Monday July 8th
Tech website BGR has reported that Apple is planning to release iOS 7 Beta 3 on Monday 8th July to its carrier partners and seeding to registered developers is expected on the same day.
BGR has been informed by trusted sources that iOS 7 beta 3 is currently scheduled to be made available to carriers for testing on July 8th. These are the same sources who accurately foretold the release timing of Apple’s last iOS 7 beta, and just like iOS 7 beta 2, it is likely that the new software will be released to developers on the same day it reaches carriers.
The release of Beta 3 on this date would be exactly two weeks after apples second beta for iOS 7.
The release of beta’s for iOS 6 last year followed a similar schedule until Apple moved the 3rd and 4th releases to a 3 week schedule.
Apple is said to still be refining many of the design elements as it proceeds through the beta testing period.