Skype issued an apology Wednesday for the outage that plagued its service Monday. The Microsoft Corp.-owned video-calling and messaging service suffered hours of downtime that kept users from placing calls and communicating with loved ones.

Skype pointed the finger at a "larger-than-usual" change to the service configuration as the culprit behind the outage. Certain versions of Skype could not properly handle the change, causing users to disconnect. All of the users attempting to reconnect subsequently created a huge amount of traffic.

"No matter how quickly we were able to resolve this issue, it would not have been quick enough," Gurdeep Singh Pall, corporate vice president for Skype at Microsoft, said in a blog post. "We know many of you needed to use Skype during the outage, and finding that you couldn't would have been incredibly frustrating. We are extremely sorry for any inconvenience caused to our users, and appreciate your patience while we addressed the issue."

The post also noted that by midnight GMT, the issues were resolved and normal service had resumed. During the outage, Skype for Business was not affected, but this provided little consolation to home users who needed to get in touch with contacts around the globe.

The incident is the third major outage in the service's existence. The first lasted for two days in 2007, and the second lasted for more than 24 hours in 2010.