Following the instruction on google play games plugin for unity, I have not been able to set it up correctly. My application crashes on signing in, with the following log output (with no more details). I've got no luck in finding a probable cause and searches seems to be out of any useful tip.
The actual error is displayed as:
Application ID () must be a numeric value. Please verify that your manifest refers to the correct project ID
The complete log output:
10-08 19:43:49.581 25688-25734/? E/linker: readlink('/proc/self/fd/49') failed: Permission denied [fd=49]
10-08 19:43:49.581 25688-25734/? E/linker: warning: unable to get realpath for the library "/data/data/com.testcompany.testapp/app_.gpg.classloader/d75c8e1bbeab9e1ddffb9d332585db71.dex". Will use given name.
10-08 19:43:49.667 25688-25734/? W/PopupManager: You have not specified a View to use as content view for popups. Falling back to the Activity content view. Note that this may not work as expected in multi-screen environments
10-08 19:43:49.675 25688-26526/? I/GamesNativeSDK: Auth operation started: SIGN IN
10-08 19:43:49.675 25688-26526/? I/GamesNativeSDK: Connecting to Google Play...
10-08 19:43:49.802 10946-10956/? W/GamesServiceBroker: Client connected with SDK 9683000, Services 9683438, and Games 37240038
10-08 19:43:49.837 10946-26540/? E/ValidateServiceOp: Application ID () must be a numeric value. Please verify that your manifest refers to the correct project ID.
10-08 19:43:49.842 25688-25688/? D/AndroidRuntime: Shutting down VM
10-08 19:43:49.846 25688-25688/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.testcompany.testapp, PID: 25688
java.lang.Error: FATAL EXCEPTION [main]
Unity version : 5.4.0f3
Device model : LGE Nexus 5
Device fingerprint: google/hammerhead/hammerhead:6.0/MRA58K/2256973:user/release-keys
Caused by: java.lang.IllegalStateException: A fatal developer error has occurred. Check the logs for further information.
at com.google.android.gms.common.internal.zze$zza.zzc(Unknown Source)
at com.google.android.gms.common.internal.zze$zza.zzv(Unknown Source)
at com.google.android.gms.common.internal.zze$zze.zzauc(Unknown Source)
at com.google.android.gms.common.internal.zze$zzd.handleMessage(Unknown Source)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
I've taken the steps needed to generate OAuth2 client ID and I've successfully applied that to GooglePlayGame plugin in unity. What could be the reason of the error message?