Skype was forced to issue a workaround for users unable to sign into their accounts while the internet telephony service worked on a permanent fix.
Reports said many users on a variety of operating systems were affected by the lockout. But Skype said in an update that the number affected was small and mainly on Skype for Windows.
Skype published a workaround for Windows, Mac OS and Linux. Skype said the problem had been identified and a fix would be issued in hours.
The service disruption comes just two weeks after Microsoft announced it had signed a deal to acquire Skype for $8.5bn.
In the past, critics have said service disruptions to Skype are proof the service is not yet ready or stable enough for business use, which is one of the challenges Microsoft will have to solve if it is to build a successful business on its Skype acquisition.
The acquisition has caused a stir in the consumer world, but read Computer Weekly's analysis of what Microsoft's Skype acquisition could mean for business.