You'll want to quickly update Microsoft Teams if you're an Android phone user. According to former XDA editor-in-chief Mishaal Rahman, Microsoft has fixed a Teams bug that led to failed 911 calls on devices using Android 10 or later. Reddit user KitchenPicture5849 discovered that having Teams installed, but not signed in, would prevent emergency calls from going through. The phone would say a call was active and ring once, but never properly initiate the connection — call logs would show nothing.
Rahman and friend Kuba Wojciechowski pinpointed the cause. While all Android calling apps will try to create a PhoneAccount class instance in the operating system, Teams was creating instances every time a user started the app "cold" — that increased the chances of a sorting problem that stopped calls from going through.
Google talked to the Reddit user and revealed that both the company and Microsoft were planning fixes. In addition to the Microsoft patch, Google is delivering an Android platform update on January 4th that should address its side of the problem. You can delete and reinstall Teams to clear any excess PhoneAccount instances, and staying logged in should prevent any mishaps.
Google said this only affected a "small number of devices." The issue, however, was the severity. This could have blocked someone from making a life-saving call through no fault of their own.