If you are running an older custom ROM (like LineageOS 14.1 or Resurrection Remix based on Android 7.1.1 Nougat), or if you’ve just flashed a fresh build of AOSP (Android Open Source Project), you’ve likely encountered the frustrating error.
: Go to Settings > Security and toggle on Unknown Sources . This allows you to install apps from outside the Play Store [3]. download google account manager 7.1.1