The co-chief executive of Kakao, the company behind South Korea’s largest mobile messaging app, has resigned after a massive outage at the weekend.
Namkoong Whon told a news conference that he felt a “heavy burden of responsibility over this incident”.
On Saturday, a fire damaged servers belonging to Kakao, shutting down its messaging, mobile banking and gaming services for more than eight hours.
Kakao’s messaging app KakaoTalk has more than 47m users in South Korea.
Speaking to reporters, Mr Namkoong apologised for the outage and said that he would “lead the emergency disaster task force overseeing the aftermath of the incident.”
Most of the firm’s services had been restored by Wednesday, although users reported that some functions remained unstable.
The outage has raised concerns about the public’s reliance on the KakaoTalk messaging app.
On Monday, South Korean President Yoon Suk-yeol said the government would examine the dominance of Kakao’s services as they were “like a fundamental national telecommunications network as far as the public is concerned”.
“If the market is distorted in a monopoly or severe oligopoly, to the extent where it serves a similar function as national infrastructure, the government should take necessary measures for the sake of the people,” he added.
There were no reports of injuries after the fire at the SK C&C data centre in Pangyo, which is south of South Korea’s capital Seoul.
Safety precautious stopped Kakao from resuming power supplies to its servers, the Yonhap news agency reported.
Mr Namkoong’s resignation leaves co-chief executive Hong Euntaek as the company’s sole leader.
Kakao said it would compensate users and businesses that were affected by the disruptions.
The company also plans to invest 460bn won ($323.9m; £285.8m) to operate its own data centre from next year, and build a second data centre in 2024.