Application not installed error Developing Android app

I developed an app recently and send it to a shop in our country called CafeBazaar to put it for sale but in an email they said:

we installed this app on Huawei P8lite with android 6.0 and we got this error "Application not installed"

Now I searched a lot about this kind of error but this is very general error in my opinion and I can't determine how should solve this error

My manifest is like this:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.GET_ACCOUNTS"/>
<uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS"/>

 <meta-data
    android:name="firebase_crashlytics_collection_enabled"
    android:value="false" />
 <application
    android:name="com.android.example.example.AppController"
    android:allowBackup="true"
    android:hardwareAccelerated="false"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:largeHeap="true"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    tools:ignore="GoogleAppIndexingWarning">

I searched a lot but usually answer was put this two below attribute in your application tag on manifest:

• android:debuggable="true"
• android:testOnly="false"

I didn't done this yet but I want to know what should I do?

After several weeks of headache i finally find solution and i put it here so if anyone had same problem can solve it.

For this problem i putted this two attribute in application tag:

• android:debuggable="false"
• android:testOnly="false"
  

and finally it solved my problem.

<application
    android:name="com.android.example.example.AppController"
    android:allowBackup="true"
    android:debuggable="false"
    android:testOnly="false" 
    android:hardwareAccelerated="false"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:largeHeap="true"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"
    tools:ignore="GoogleAppIndexingWarning">