Cannot resolve symbol 'r3'

Hello, I'm trying to build a corda account for my project. I've installed the libraries inside of my build.gradle file. But, it seems have problem when I import the com.r3.corda.lib.accounts.contracts and com.r3.corda.lib.accounts.workflows inside of the file. Can I know how to solve the issues? (The issue is Cannot resolve symbol 'r3' and so on"