Failed to create signed assembly after updating Android version in Cordoba

Question

I worked with <5 version of the Android platform in my hybrid application. Now I updated the version by deleting first ionic platform rm androidand then ionic platform add android@5.0.0. With the previous version, I was able to easily create a signed release build

cordova build android --release --buildConfig=build.json -- --gradleArg=-PcdvMinSdkVersion=16

but after adding this version android@5.0.0, when I run the build command, it gives meandroid-release-unsigned.apk

Note: I use the same key store as before, using

Update:

{ 
"android": {
        "release": {
        "keystore": "C:\\Path\\To\\Keystores\\theapp.keystore",
        "storePassword": "",
        "alias": "thealias",
        "password" : "",
        "keystoreType": ""
    } 
}