Cannot resolve symbol default_web_client_id in Firebase's Android Codelab

Question

I am trying to learn Firebase, so I went through the Android Codelab. The project they gave me however, had an error:

Cannot resolve symbol default_web_cl

Answer 1

classpath 'com.google.gms:google-services:4.1.0'

has a problem. instead use:

classpath 'com.google.gms:google-services:4.2.0'