I installed official version of android studio 3.0, so now all of my project(even a new project!) failed at gradle sync.
to know, i deleted all of my gardle files and studio setting in user Directory and downloaded all of them again :(
in this picture i have got this problem:
first same error in every project
and here's some details: details
here is my gradle version in build.gradle(project:AndroidStudio)
classpath 'com.android.tools.build:gradle:3.0.0'
and i have gradle-4.1-all.zip
in my GRADLE_USER_HOME