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Docomo 5G SA Down Nationwide: Calls, Data and SMS Fail Again

By Outages Now Editors

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Photo: Rahul Shah / Pexels

NTT Docomo’s 5G SA (standalone) service failed across Japan on Nov. 11, leaving subscribers unable to make voice calls, use mobile data or send SMS, according to Docomo’s announcements as summarized by the site note. The incident began at 10:34 AM, local time, and the sources do not name a time zone. By 5:15 PM, Docomo’s eighth report said service had returned with some exceptions.

Docomo has not declared full restoration, and it has not announced a cause. It told the public it has found no sign of unauthorized access or a cyberattack, a statement the Yomiuri Shimbun also reported.

Who was affected

The outage covered the whole country but only customers on 5G SA. Docomo said other 5G service, 4G, MVNOs (companies that sell mobile plans over Docomo’s network) and emergency calls were not affected.

A 5G icon on a phone screen does not tell a user which type of 5G they are on. 5G SA is a separate system from the older style of 5G, which also uses 4G equipment. Customers unsure of their plan can check contract details in My docomo once connections work again.

What Docomo is asking users to do

In its eighth report on Nov. 11, Docomo listed two steps for people who cannot connect: restart the phone, or switch airplane mode on and then off. Both force the device to reconnect to the network.

Guidance from the Nov. 5 outage told users to select 4G. That instruction does not appear in the Nov. 11 report, so it should not be assumed to apply this time.

How it compares with the Nov. 5 outage

The 5G SA service also failed from Nov. 5 to 6. Keitai Watch reported that incident came from a memory error in switching equipment combined with database update work, which caused a surge of communication traffic. It affected up to about 1,587,000 people and took roughly 14 hours to fix.

Whether the two failures share a cause is not known. The cause of the Nov. 11 outage is under investigation, and the same service failing twice does not mean the same fault is behind both.

Why it matters

A phone that cannot connect also cuts off two-factor log-ins for work, maps, cashless payments and contact with family. Customers also lose the ability to look up outage information on the same device. The site note points to home or office Wi-Fi, a line from another carrier or an agreed meeting place as backups.

Emergency calls were not affected in this case. For general trouble reaching 119 during a network failure, Japan’s Fire and Disaster Management Agency advises using a public phone, asking a nearby person or shop to place the call, or going to a fire station.

What to watch next

  • When Docomo announces full restoration.
  • The cause of the Nov. 11 outage and the number of people affected.
  • Whether the company announces preventive measures or compensation.

Docomo posts updates under Important Notices on its website. The information here was confirmed as of 5:56 PM on Nov. 11, and the cause and restoration status may change.

Source: note

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