Skype has issued a public apology after its widely-used app bogged down Monday.

"We are extremely sorry for any inconvenience caused to our users, and appreciate your patience while we addressed the issue," Skype posted on its official blog site.

The popular video-chatting service explained that the problem arose when it "released a larger-than-usual configuration change, which some versions of Skype were unable to process correctly therefore disconnecting users from the network."

"When these users tried to reconnect, heavy traffic was created and some of you were unable to use Skype's free services, including messaging, presence, and contact list management," Skype's statement said.

"Others could not sign in or out of Skype altogether, or make calls to landlines or mobile phones. [However], Skype for Business was not impacted."

Skype said that although the issue had already been resolved by midnight of the same day, it realized the significant impact which the system's temporary downtime had on users across the globe.

No matter how quickly we were able to resolve this issue, it would not have been quick enough," the statement said.

"We know many of you needed to use Skype during the outage, and finding that you couldn't would have been incredibly frustrating," it added.

Meanwhile, Skype users took to Twitter to air their frustration over their inability to access the instant-messaging app, reported the Independent.

People complained that they were unable to make Skype calls to contacts who showed up offline even they (users) had already logged in.

"@CarlyPage_ contacts are all appearing offline but it's still letting me send some messages," Mike Jennings (@mikejjenings) tweeted.

"guys can somebody please confirm if Skype is down before I throw my MacBook at something," Carly Page (@CarlyPage_) posted.

"#Skype is down and I'm having a really productive morning. Coincidence, right?" Gavin Mills (@EpiphamyG) ranted on his account.

With this recent incident, Skype has learned that it can't afford to let its guard - or app - down.