Can't sign APK with R8

Question

I am preparing to deploy my app to the playstore, my current expertise is based on proguard, It seems that now we have to use R8, so I followed the guide on the developer site for Android, as R8 can use the same pro guard files and configurations, I just simply created and added the rules needed to work. Just when I prepare to sign it up I get this error:

C:\Users\bgatica\.gradle\caches\transforms-2\files-2.1\10d9066f27f47bf4c88827e811c3eb8a\obfuscation-dictionary.txt'

I went to that path and looks like those file are generated by gradle? I searched on the internet for a similar mistake or a tutorial where they guide to create this files but there is none of it, Could you help me?

This is the configuration I have

buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            multiDexKeepFile file('multidex-config.txt')
        }
    }

This is my configuration for Proguard

-dontpreverify
-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontskipnonpubliclibraryclassmembers
-dontpreverify
-verbose
-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*,!code/allocation/variable
-repackageclasses ''
-allowaccessmodification
#-optimizations !code/simplification/arithmetic
-keepattributes *Annotation*
-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keep class org.kobjects.** { *; }
-keep class org.ksoap2.** { *; }
-keep class org.kxml2.** { *; }
-keep class org.xmlpull.** { *; }
-dontwarn org.kobjects.**
-dontwarn org.ksoap2.**
-dontwarn org.kxml2.**
-dontwarn org.xmlpull.v1.**
-dontwarn android.app.**
-dontwarn android.support.**
-dontwarn android.view.**
-dontwarn android.widget.**
-dontwarn com.google.common.primitives.**
-dontwarn **CompatHoneycomb
-dontwarn **CompatHoneycombMR2
-dontwarn **CompatCreatorHoneycombMR2
-dontwarn javax.annotation.Nullable
-dontwarn com.google.**
-keep public class * extends android.view.View {
    public <init>(android.content.Context);
    public <init>(android.content.Context, android.util.AttributeSet);
    public <init>(android.content.Context, android.util.AttributeSet, int);
    public void set*(...);
}
-keepclasseswithmembernames class * {
    native <methods>;
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
    public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keepclassmembers class * extends android.app.Activity {
   public void *(android.view.View);
}
-keepclassmembers class * extends android.content.Context {
   public void *(android.view.View);
   public void *(android.view.MenuItem);
}
-keepclassmembers class * implements android.os.Parcelable {
    static ** CREATOR;
}
-keepclassmembers class **.R$* {
    public static <fields>;
}
-keepclassmembers class * {
    @android.webkit.JavascriptInterface <methods>;
}
-dontwarn android.support.**
-dontwarn com.google.android.gms.**
#-optimizationpasses 5
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontpreverify
-verbose
#-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable
# http://stackoverflow.com/questions/4525661/android-proguard-cant-find-dynamically-referenced-class-javax-swing
-dontwarn java.awt.**
-dontnote java.awt.**
-dontwarn com.badlogic.gdx.jnigen.**
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.android.vending.licensing.ILicensingService
-keepclasseswithmembernames class * {
    native <methods>;
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keepclassmembers class * extends android.app.Activity {
   public void *(android.view.View);
}
-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}
-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}
-keepclassmembers class **.R$* {
    public static <fields>;
}
 -keepattributes *Annotation*
 -keepclassmembers class ** {
     @org.greenrobot.eventbus.Subscribe <methods>;
 }
 -keep enum org.greenrobot.eventbus.ThreadMode { *; }
 # Only required if you use AsyncExecutor
 -keepclassmembers class * extends org.greenrobot.eventbus.util.ThrowableFailureEvent {
     <init>(java.lang.Throwable);
 }
 -keepclassmembers class ** {
     public void onEvent*(**);
 }
-keepattributes Signature
-keep class okhttp3.** { *; }
-keep interface okhttp3.** { *; }
-dontwarn okhttp3.**
# Ignore annotation used for build tooling.
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

# Ignore JSR 305 annotations for embedding nullability information.
-dontwarn javax.annotation.**

# Guarded by a NoClassDefFoundError try/catch and only used when on the classpath.
-dontwarn kotlin.Unit

# Top-level functions that can only be used by Kotlin.
-dontwarn retrofit2.KotlinExtensions
-dontwarn retrofit2.KotlinExtensions$*

# With R8 full mode, it sees no subtypes of Retrofit interfaces since they are created with a Proxy
# and replaces all potential values with null. Explicitly keeping the interfaces prevents this.
-if interface * { @retrofit2.http.* <methods>; }
-keep,allowobfuscation interface <1>
-dontwarn okio.**
-dontwarn retrofit2.Platform$Java8