A man reads a KaKaoT's notice explaining its systematic malfunction, Oct. 16. Yonhap

A fire at a data center near Seoul has disrupted services of Korea's dominant messenger and internet portal for a day, affecting nearly all sectors of the country, even finance and transportation.

The fire broke out at 3:33 p.m. Saturday at the building of SK CC located in Pangyo, just south of Seoul, which houses the data centers for Naver and Kakao, Korea's two major tech giants.

Right after the fire started, the power was cut off at the data center for safety reasons. The fire was extinguished some eight hours later.

But KakaoTalk has been suffering a massive service malfunction for nearly a day, along with its affiliated services like Kakao Pay, a mobile payment and digital wallet service, and Kakao T, a transportation service app.

KakaoTalk is the most popular mobile messenger in the country of 51 million people, with 43 million monthly active users.

Users said they are experiencing inconvenience in their daily lives and business as KakaoTalk chat rooms are widely used as a tool to receive exclusive messages, coupons and other real-time information. The messenger, launched in 2010, also offers a platform to help users buy real-life goods, play games and access banking services.

"I needed to receive a photo from my business partner through KakaoTalk. But I had to go through an inconvenient process to get the photo through email because of the KakaoTalk disruption," said a KakaoTalk user, asking for anonymity. "I should've used Telegram."

Some people complained of the difficulty in making mobile payments and online transactions through Kakao Pay.