android- remove black background from launcher icon api 26

I've a big problem with launcher icon in api 26

I've png with transparent background , But it gets black on transparent parts

this is the result :

it's not for the theme because other apps has no background

this is my manifest :

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:roundIcon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="false"
    android:theme="@style/AppTheme">

this is the code for api 26

<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
<background android:drawable="@mipmap/ic_launcher_background"/>
<foreground android:drawable="@mipmap/ic_launcher_foreground"/>

this is the ic_launcher_background file , it's an transparent image :

this is the ic_launcher_foreground file :

how can I solve this ? how can I get rid of the black background ?