签署androidbundle时出错：任务'：app：signReleaseBundle'执行失败

我试图构建 Flutter android 应用程序的发布版本并收到以下错误：（Macbook M1 使用终端命令）

* What went wrong:                                                      
Execution failed for task ':app:signReleaseBundle'.                     
> A failure occurred while executing com.android.build.gradle.internal.tasks.Workers$ActionFacade
   > kotlin.KotlinNullPointerException (no error message)

我不知道如何解决这个问题。相关部分的 android/app/build.gradle 如下所示：

    signingConfigs {
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }
    buildTypes {
        release {
            signingConfig signingConfigs.release
        }
    }
}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support:multidex:2.0.1'
}