After over a 24-hour outage, Microsoft's Bing, Copilot, and Copilot in Windows services are back online worldwide, with no information released as to what caused the problem.

The massive outage began around 3 AM EST on Thursday and mainly affected users in Asia and Europe, making it impossible for many to access these services.

During the outage, Bing.com showed either a blank page or a 429 HTTP code error, though direct Bing search still worked. 

DuckDuckGo, which uses Bing AI, was also offline with an error message, "There was an error displaying the search results. Please try again."

ChatGPT's internet search features, which Bing powers, were also down, as confirmed by OpenAI.

Microsoft shared updates throughout the day, initially stating, "We're working to find the cause of the issue. More information can be found in the admin center under CP795190."

Later, the company said they were switching requests to alternative service components to speed up recovery.

Slowly, services started returning, with DuckDuckGo being the first to work again, followed by partial recovery of Bing.com and Copilot.

Microsoft's telemetry data showed a steady recovery, with ongoing investigations to determine the root cause. However, even today, users outside the United States reported being unable to use Copilot.

Today, at approximately 1:30 PM EST, Microsoft announced that Bing and Copilot services were fully restored, which BleepingComputer confirmed in our own tests.

The Android, iOS, and Windows apps, which also had issues, started working again.

In a statement, Microsoft confirmed the issue had been resolved, and it was due to a problem with an internal service-to-service call.

"We've shared the following preliminary root cause with customers in admin center: An internal service-to-service call within the underlying platform leveraged by Copilot and Bing traffic was not performing as expected in relation to a specific request that checks a user's eligibility status," 

by Microsoft Spokesperson