KDDI Corp., the operator of au mobile phone services, said Sunday the data communication disruption the previous night has affected up to 6.15 million cellphones and smartphones.
The incident, in which the proprietary ezweb e-mail service was disrupted from around 8:35 p.m. Saturday until before midnight Sunday, was the largest disruption for KDDI since August 2003, when about 12.79 million of its cellphones were affected by a communications system trouble, it said.
The latest trouble was caused by a failed electric supply to its computer servers for e-mail services, but the incident had no impact on voice calls and Internet access, it said, adding that the failure may have resulted from an increase in data communication traffic for smartphones.
The disruption came on the heels of one on Thursday, in which some au smartphones temporarily failed to access the Internet, affecting up to 1.3 million users.