title: Google Play: Bundle was not signed
body: <p>I'm creating app in Kotlin and I paid Google developer account. But there is some problem with upload .aab file: <code>The Android App Bundle was not signed</code>. I readed all topics at Stackoverflow about it and tried all solutions. Not works for me.
  <code>signingConfig signingConfigs.release</code> in <code>build.gradle</code> ends with this error: <code>Could not get unknown property 'release' for SigningConfig</code>. It works only when I set <code>signingConfig</code>. I'm using also this: <code>minifyEnabled false</code> and <code>debuggable = false</code>. So what another I must to try? There exists some new solution for year 2021?!</p>
  <p>My build.gradle:</p>
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'kotlin-android'
  apply plugin: 'kotlin-kapt'
  
  android {
      compileSdkVersion 31
      buildToolsVersion &quot;30.0.3&quot;
  
      defaultConfig {
          applicationId '...'
          minSdkVersion 21
          targetSdkVersion 31
          versionCode 1
          versionName &quot;1.00&quot;
          testInstrumentationRunner &quot;androidx.test.runner.AndroidJUnitRunner&quot;
          manifestPlaceholders[&quot;hostName&quot;] = &quot;...&quot;
      }
  
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
              signingConfig
              debuggable = false
          }
          applicationVariants.all{
              variant -&gt;
                  variant.outputs.each{
                      output-&gt;
                          def name = &quot;...apk&quot;
                          output.outputFileName = name
                  }
          }
      }
      buildFeatures{
          dataBinding = true
          viewBinding = true
      }
  }
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
  
      implementation 'com.google.android.material:material:1.4.0'
      implementation 'androidx.navigation:navigation-fragment-ktx:2.3.5'
      implementation 'com.github.amitshekhariitbhu.Fast-Android-Networking:android-networking:v1.0.2'
      implementation 'androidx.legacy:legacy-support-v4:1.0.0'
  
  }
  </code></pre>