Intellij + Groovy + Spock, cannot resolve symbol 'spock'

i am using spock framework for tests and everything worked great, until today, do not know what happened. Intellij says "Configure Groovy sdk" so i download groovy sdk 2.4.9 and configure it, but in my test class in import line

import spock.lang.Specification

intellij says "cannot resolve symbol spock". Any suqqestions?