When there is an firebase_auth/invalid-cert-hash

firebase-auth-invalid-cert-hash

go to <project>\build\app\outputs\apk\debug
in a cmd
  keytool -printcert -jarfile app-debug.apk
  sha-1 copy then
  go to firebase and project overview then go to the connected apps
  click the setting icon in android
  paste the sha1 as a new fingerprint
 for ios setup https://www.youtube.com/watch?v=k7TVYn5jwQk
  go to googleservices-info.plist in ios/runner
  then get the reverse client id
  if that is not there then delete the file and rerun the flutterfire configure command
  then you need xcode
 but the android is ok
 in the video the tutorial is showing for ios
when there is an error with asynchronous just restart or rebuild the app