Microsoft restores Outlook and Teams after an outage of over a day

TL;DR in 30 sec

• Microsoft said on 14 November that it had restored its 365 services to “the remaining impacted customers and regions”, Digital Trends and CNBC reported.
• The outage began on 12 November and hit Outlook email, Teams, SharePoint, Copilot and other services, according to MediaNama.
• Microsoft traced the cause to “an issue during an earlier network capacity upgrade” and said it found no malicious activity, CNBC reported.
• In India, IndiGo, Akasa Air and Equitas Small Finance Bank said their email support was affected, Inc42 reported.

What happened

Microsoft put the start of the incident at 18:26 GMT on 12 November, just before midnight in India, The Register reported. The first to go down was Exchange Online, the service that runs Outlook email for businesses, according to the same outlet.

At first, Microsoft said users in the Americas could not reach their mailboxes. Later, it said users in any region could be affected, MediaNama reported. The incident, numbered MO1550821, also covered Teams, SharePoint Online, Microsoft 365 Copilot, Planner, To Do and Intune, according to MediaNama.

Microsoft said servers were failing automated health checks and dropping out of service, which put more load on the ones still running, The Register reported. Even servers that were restarted became unresponsive again once traffic returned to them, Digital Trends reported.

On 13 November, Microsoft apologised. “We are deeply sorry for the disruption this incident has caused our customers and partners,” the company said, as quoted by CNBC. It also extended the time it would keep trying to deliver delayed emails to 48 hours, CNBC reported.

Engineers then patched an authentication and routing component and brought traffic back step by step, Digital Trends reported. On 14 November, Microsoft said on X that service had been restored to the remaining customers and regions, according to Digital Trends.

Why it matters for India 🇮🇳

The outage reached 74 countries, including India, Inc42 reported. By 10 am on 13 November, complaints about Outlook from India on Downdetector, a site that tracks outages, had reached nearly 4,000, according to Inc42.

IndiGo said its email support was affected, Inc42 reported. Akasa Air asked passengers to use its 24-hour care centre or social media, and Equitas Small Finance Bank asked customers to call its helpline instead of writing, the same report said. Air India temporarily rerouted its emails but said its flights were not affected, CNBC reported.

The HR software startup Keka said tasks such as making offer letters and scheduling interviews were affected, according to Inc42.

Background

More than 430 million people use Microsoft 365 apps, according to Microsoft’s website, as cited by Inc42.

According to Inc42, Microsoft’s service agreement promises 99.9% availability each month. When it falls short, eligible customers can get credits on their monthly fee, subject to conditions.

The outage came a week after Microsoft warned that its older Exchange Server 2016 and 2019 email software, which it no longer supports, is “permanently vulnerable”, The Register reported.

Different perspectives

Microsoft said it was not aware of any malicious activity behind the outage, according to The Register and CNBC. Digital Trends reported that the company also ruled out AI as the cause.

Jos Poortvliet, co-founder of Nextcloud, which offers an alternative to Microsoft’s tools, said, “This incident shows how dependent organizations are on a single ecosystem,” as quoted by The Register.

Mark Boost, chief executive of the cloud company Civo, said, “Every technology provider will experience failures,” and argued that the bigger worry is critical services resting with a few companies, The Register reported.

In the UK, Chi Onwurah, who chairs the House of Commons Science and Technology Committee, said the outage showed a lack of resilience in the country’s digital infrastructure, according to The Register. Australia’s Home Affairs Minister Tony Burke compared it to the faulty-update incident of 2024 involving CrowdStrike, CNBC reported.

Inc42 reported that there was no evidence linking the outage to Microsoft’s recent job cuts, and that Microsoft had not blamed it on staffing.

Open questions 🤔

• What exactly went wrong in Microsoft’s network upgrade, and what will it change to stop it happening again?
• Will Indian businesses that lost email during the outage receive service credits from Microsoft?
• How many people and businesses in India were affected in all?

What to watch next

Microsoft has said it will publish a post-incident report on the root cause and the steps it will take, MediaNama reported. It has not given a date.