Android Studio error : Cannot open a library at 'FileMapping(from=....core.jar, to=....jetified-core.jar)

I am trying to use the Rocket.Chat APIs in one of my projects. But after adding the jars and completing the gradle things when I tried to run the App, I am getting the error like "Cannot open a library at ‘FileMapping(from=/home/rls/AndroidStudioProjects/RocketChatIntegration/my-app-android/app/libs/core.jar, to=/home/rls/.gradle/caches/transforms-1/files-1.1/core.jar/8bd996c777fadbbb76d825eb83614401/jetified-core.jar)’
Any suggestions why this is coming. Please suggest.