Most Korean cryptocurrency exchanges using the Amazon Web Services (AWS) suffered a connection failure Thursday morning owing to a network error in Amazon’s cloud services.

The malfunction hit most exchanges operating in Korea around 9 a.m., causing investors to experience inconvenience. Access to such exchanges as Upbit, GDAC, OKCoin, Chainb, CoinPlus, Bitland, Gopax, Hanbitco, Coinrail, Bitsonic, Coinone and Allstarbit was halted. AWS underwent a domain name server (DNS) issue but services have been restored later.

In an emergency notice released at 9 a.m., Upbit said, “Customers cannot use our service temporarily because of the malfunctioning server. We will complete our emergency inspection as quickly as possible.” Upbit also said orders filed before and after the network failure would be called off. At 8:45 a.m., Coinone also put a notice reading, “Services are suspended temporarily to conduct an emergency inspection of the network.”

The web pages and apps of many other Korean companies including Coupang, Yanolja and Baedal Minjok were not accessed.

Experts attributed the breakdown to the DNS issue that hit AWS. Officials at Seoul-based crypto exchanges said most companies using AWS suffered similar problems. But their services were restored as the cause was identified soon. Digital currencies kept at crypto exchanges reportedly remained safe.

In the meantime, such exchanges as Bithumb not using AWS were not affected by the network failure. An executive at a crypto exchange expressed concern that “the latest incident might erode confidence in exchanges further.”

AWS accounts for around 40% of Korea’s corporate public cloud market. Industry watchers speculated that a number of companies would be hurt by the failure, but it remains to be seen whether AWS will compensate for their losses.

/Eundong Shin·Jaeyeon Won Reporter edshin@decenter.kr

Eundong Shin Reporter,Jaeyeon Won Reporter