Microsoft 365 service error causes Outlook and Exchange disruption

Users had trouble accessing their mailboxes for almost two days

The Microsoft 365 online work suite experienced service outage issues in recent days. Multiple users reported that they were not able to access their mailboxes through any platform, reported network security and ethical hacking experts from the International Institute of Cyber Security.

Some users also reported delays of up to three hours in the sending and receiving of their emails; in addition to some other failures in the service (users received multiple times the same message).

Microsoft 365 is an online service that includes Office 365, Windows 10, and Windows Enterprise Mobility and Security. According to experts in network security, in the case of an online platform, the drawbacks that are presented can be serious. In this case, all users of Microsoft 365 were affected by the same error of this product in the cloud.

Through Twitter, the Microsoft 365 team mentioned: “We have determined that a subset of the domain controller infrastructure is not responding. We are implementing some measures to mitigate the drawbacks. More details can be found in the Microsoft 365 Administration Center”.

As Microsoft concluded its investigation into the incident, users around the world continued to report service failures that prevented them from sending and receiving their personal and business messages for almost two days.

Microsoft later reported that “a higher-than-expected queuing in the platform’s authentication infrastructure could be the cause of the incident. We are now working to identify the causes of these queuing as well as impact mitigation”.

A few hours later, Microsoft reported via Twitter: “Our telemetry data indicate flaws in the connection timeout within the Exchange authentication infrastructure, which generated this incident”.

After two days of inactivity, Microsoft 365 users began reporting that the incident (identified as EX172491) had been completely eliminated, according to network security experts.