On Monday, Nippon Telegraph and Telephone’s regional subsidiaries announced that their internet and landline telephone services had experienced significant disruptions throughout Japan.
The problem began on the first business day of the 2023 fiscal year, and services were restored hours after the incident.
NTT’s optical line services, which are utilized by SoftBank and NTT Docomo, also experienced connectivity issues. Following the disruptions at NTT, the communications ministry dispatched officials to NTT East and NTT West to investigate the root cause of the problem.
NTT East confirmed that service disruptions began at approximately 7:10 a.m., affecting optical network service subscribers in Tokyo, Kanagawa Prefecture, and Hokkaido.
Emergency calls were temporarily unavailable, and the company requested that customers utilize mobile or public phones instead. NTT East restored its services by 10 a.m.
Similarly, NTT West reported similar disruptions in several areas, including Osaka, Ishikawa, and Ehime prefectures. The company was able to resolve the issue in approximately one and a half hours.
These disruptions follow a series of network-related problems that have occurred recently in the industry. In 2022, mobile carriers such as KDDI and NTT Docomo also experienced significant service glitches.