Microsoft Teams is experiencing an outage that has blocked access and limited features for some users.

The issue began around 11 a.m. Eastern Time Friday and grew rapidly in scope, according to outage tracker DownDetector. Users have complained of an inability to access the service, delays in sending and receiving messages, and issues displaying graphics.

Microsoft said in messages on X, the social network formerly known as Twitter, that it has identified “a networking issue impacting a portion of the Teams service” and had moved some services to backup systems. At roughly 1:30 p.m. Eastern Time, the company reported that the backup transition was complete for Europe, Africa and the Middle East and that its tracking systems were showing improvements.

The company said that backup switchovers for North and South American were ongoing. Outage reports on DownDetector had fallen to almost half their peak level as of 3 p.m. Eastern Time.

But X users based in the U.S. continued to complain about Teams service issues, with several sarcastically thanking Microsoft for fixing the problem quickly in regions where the workday is already over.