Google has since acknowledged the issue with the app and is reportedly working on a fix that will be pushed out in the form of an update. According to a Google employee who is reportedly familiar with the situation, “Thanks for your patience! The engineers believe they have found a fix! As soon as the fix is released I’ll let you know! Unfortunately, I wasn’t provided a timeline, so stay tuned!”
In the meantime for those who have to use the Google Hangouts 2.1 on their Android phone, it has been suggested that you downgrade to an older version of the app. This can be done by downloading an older APK that you can find online, although we have to caution users about this because installing apps outside of Google Play can be dangerous, since some malware can be disguised as regular apps to trick unsuspecting users.
Alternatively you can just ensure that your phone is constantly charged, especially if you’re planning on using the app quite a lot but don’t want to downgrade to an older version. In the meantime we’ll be keeping our eyes and ears peeled for the release of the update that should fix it.