backFlutterManifest.xml

// ... 생략

    <uses-permission android:name="android.permission.INTERNET" />

    <application
        android:icon="@mipmap/ic_launcher"
        android:label="andtest"
        android:usesCleartextTraffic="true">
        <service
            android:name=".MyIntentService"
            android:exported="true"
            android:enabled="true"
            tools:ignore="Instantiatable"></service>
            
// ... 생략