Build.gradle error

whenever i open build.gradle of app folder in android studio. This file shows these errors:-
Cannot resolve symbol ‘Properties’
Cannot resolve symbol ‘GradleException’

due to this i am not able to connect my flutter project with firebase

Does it build from the command line? If yes, it seems to not be a Gradle problem, but an AS problem. If so, try to invalidate caches and restart. If that didn’t help, you should probably ask Google support or JetBrains support about it.