NTT Docomo said on November 5 around midday that its mobile phone services had become difficult to use nationwide. Voice calls, data communications and SMS are all affected, and the disruption extends to MVNOs — smaller carriers that lease capacity from a major network operator — that run on Docomo lines.
Docomo is still confirming when the fault began and whether emergency calls have been affected. It said it will give details of the impact and an estimate for restoration once it has verified them.
The same morning, Docomo said it had taken its online shop and the My docomo customer site offline to investigate the cause, judging that "there is a high possibility that unauthorized access was made from outside." The company has not said whether the two events are connected.