com.google.firebase.FirebaseNetworkException: A network error (such as timeout, interrupted connection or unreachable host) has occurred. #313

I am a beginner and I followed all the steps mentioned in the codelab.
But I stuck here. I am okay to adjust if a codelab is not compatible to all the versions, and hence I will debug and fix issues. But I am tired of lots of issues which not have any clear information and support from firebase. Here is the stacktrace.
A sign-in error occurred. com.google.firebase.FirebaseNetworkException: A network error (such as timeout, interrupted connection or unreachable host) has occurred. at com.google.android.gms.internal.firebase-auth-api.zzadg.zza(com.google.firebase:firebase-auth@@23.1.0:15) at com.google.android.gms.internal.firebase-auth-api.zzaef.zza(com.google.firebase:firebase-auth@@23.1.0:21) at com.google.android.gms.internal.firebase-auth-api.zzady.zza(com.google.firebase:firebase-auth@@23.1.0:32) at com.google.android.gms.internal.firebase-auth-api.zzaea.zza(com.google.firebase:firebase-auth@@23.1.0:71) at com.google.android.gms.internal.firebase-auth-api.zzade.zza(com.google.firebase:firebase-auth@@23.1.0:46) at com.google.android.gms.internal.firebase-auth-api.zzzv.zza(com.google.firebase:firebase-auth@@23.1.0:3) at com.google.android.gms.internal.firebase-auth-api.zzaeo.zza(com.google.firebase:firebase-auth@@23.1.0:67) at com.google.android.gms.internal.firebase-auth-api.zzadv.zza(com.google.firebase:firebase-auth@@23.1.0:18) at com.google.android.gms.internal.firebase-auth-api.zzzk.zze(com.google.firebase:firebase-auth@@23.1.0:128) at com.google.android.gms.internal.firebase-auth-api.zzadh.zze(com.google.firebase:firebase-auth@@23.1.0:92) at com.google.android.gms.internal.firebase-auth-api.zzabp.zza(com.google.firebase:firebase-auth@@23.1.0:15) at com.google.android.gms.internal.firebase-auth-api.zzaeh.run(com.google.firebase:firebase-auth@@23.1.0:2) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) at com.google.firebase.concurrent.CustomThreadFactory.lambda$newThread$0$com-google-firebase-concurrent-CustomThreadFactory(CustomThreadFactory.java:47) at com.google.firebase.concurrent.CustomThreadFactory$$ExternalSyntheticLambda0.run(D8$$SyntheticClass:0) at java.lang.Thread.run(Thread.java:923)