Screen doesn't turn off

Hi,
My app doesn’t let the screen go to sleep neither on android nor on ios (after being inactive, no interaction with screen, for several minutes). I did not install any plugin to do so and am wondering why. Here is my config.xml file:

<?xml version='1.0' encoding='utf-8'?>
<widget id="com.ionicframework.***" version="0.0.12" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
    <name>***</name>
    <description>****</description>
    <author email="***" href="">***</author>
    <content src="index.html" />
    <access origin="*" />
    <allow-navigation href="http://ionic.local/*" />
    <allow-navigation href="***" />
    <allow-navigation href="http://localhost:8080/*" />
    <allow-intent href="http://*/*" />
    <allow-intent href="https://*/*" />
    <allow-intent href="tel:*" />
    <allow-intent href="sms:*" />
    <allow-intent href="mailto:*" />
    <allow-intent href="geo:*" />
    <platform name="android">
        <allow-intent href="market:*" />
        <icon density="ldpi" src="resources/android/icon/drawable-ldpi-icon.png" />
        <icon density="mdpi" src="resources/android/icon/drawable-mdpi-icon.png" />
        <icon density="hdpi" src="resources/android/icon/drawable-hdpi-icon.png" />
        <icon density="xhdpi" src="resources/android/icon/drawable-xhdpi-icon.png" />
        <icon density="xxhdpi" src="resources/android/icon/drawable-xxhdpi-icon.png" />
        <icon density="xxxhdpi" src="resources/android/icon/drawable-xxxhdpi-icon.png" />
        <splash density="land-ldpi" src="resources/android/splash/drawable-land-ldpi-screen.png" />
        <splash density="land-mdpi" src="resources/android/splash/drawable-land-mdpi-screen.png" />
        <splash density="land-hdpi" src="resources/android/splash/drawable-land-hdpi-screen.png" />
        <splash density="land-xhdpi" src="resources/android/splash/drawable-land-xhdpi-screen.png" />
        <splash density="land-xxhdpi" src="resources/android/splash/drawable-land-xxhdpi-screen.png" />
        <splash density="land-xxxhdpi" src="resources/android/splash/drawable-land-xxxhdpi-screen.png" />
        <splash density="port-ldpi" src="resources/android/splash/drawable-port-ldpi-screen.png" />
        <splash density="port-mdpi" src="resources/android/splash/drawable-port-mdpi-screen.png" />
        <splash density="port-hdpi" src="resources/android/splash/drawable-port-hdpi-screen.png" />
        <splash density="port-xhdpi" src="resources/android/splash/drawable-port-xhdpi-screen.png" />
        <splash density="port-xxhdpi" src="resources/android/splash/drawable-port-xxhdpi-screen.png" />
        <splash density="port-xxxhdpi" src="resources/android/splash/drawable-port-xxxhdpi-screen.png" />
    </platform>
    <platform name="ios">
        <allow-intent href="itms:*" />
        <allow-intent href="itms-apps:*" />
        <icon height="57" src="resources/ios/icon/icon.png" width="57" />
        <icon height="114" src="resources/ios/icon/icon@2x.png" width="114" />
        <icon height="40" src="resources/ios/icon/icon-40.png" width="40" />
        <icon height="80" src="resources/ios/icon/icon-40@2x.png" width="80" />
        <icon height="120" src="resources/ios/icon/icon-40@3x.png" width="120" />
        <icon height="50" src="resources/ios/icon/icon-50.png" width="50" />
        <icon height="100" src="resources/ios/icon/icon-50@2x.png" width="100" />
        <icon height="60" src="resources/ios/icon/icon-60.png" width="60" />
        <icon height="120" src="resources/ios/icon/icon-60@2x.png" width="120" />
        <icon height="180" src="resources/ios/icon/icon-60@3x.png" width="180" />
        <icon height="72" src="resources/ios/icon/icon-72.png" width="72" />
        <icon height="144" src="resources/ios/icon/icon-72@2x.png" width="144" />
        <icon height="76" src="resources/ios/icon/icon-76.png" width="76" />
        <icon height="152" src="resources/ios/icon/icon-76@2x.png" width="152" />
        <icon height="167" src="resources/ios/icon/icon-83.5@2x.png" width="167" />
        <icon height="29" src="resources/ios/icon/icon-small.png" width="29" />
        <icon height="58" src="resources/ios/icon/icon-small@2x.png" width="58" />
        <icon height="87" src="resources/ios/icon/icon-small@3x.png" width="87" />
        <splash height="1136" src="resources/ios/splash/Default-568h@2x~iphone.png" width="640" />
        <splash height="1334" src="resources/ios/splash/Default-667h.png" width="750" />
        <splash height="2208" src="resources/ios/splash/Default-736h.png" width="1242" />
        <splash height="1242" src="resources/ios/splash/Default-Landscape-736h.png" width="2208" />
        <splash height="1536" src="resources/ios/splash/Default-Landscape@2x~ipad.png" width="2048" />
        <splash height="2048" src="resources/ios/splash/Default-Landscape@~ipadpro.png" width="2732" />
        <splash height="768" src="resources/ios/splash/Default-Landscape~ipad.png" width="1024" />
        <splash height="2048" src="resources/ios/splash/Default-Portrait@2x~ipad.png" width="1536" />
        <splash height="2732" src="resources/ios/splash/Default-Portrait@~ipadpro.png" width="2048" />
        <splash height="1024" src="resources/ios/splash/Default-Portrait~ipad.png" width="768" />
        <splash height="960" src="resources/ios/splash/Default@2x~iphone.png" width="640" />
        <splash height="480" src="resources/ios/splash/Default~iphone.png" width="320" />
        <icon height="1024" src="resources/ios/icon/icon-1024.png" width="1024" />
        <splash height="2732" src="resources/ios/splash/Default@2x~universal~anyany.png" width="2732" />
        <edit-config file="*-Info.plist" mode="merge" target="NSCameraUsageDescription">
            <string>To share photos on *</string>
        </edit-config>
        <edit-config file="*-Info.plist" mode="merge" target="NSPhotoLibraryUsageDescription">
            <string>To share photos on *</string>
        </edit-config>
    </platform>
    <preference name="AllowInlineMediaPlayback" value="true" />
    <preference name="webviewbounce" value="false" />
    <preference name="UIWebViewBounce" value="false" />
    <preference name="DisallowOverscroll" value="true" />
    <preference name="android-minSdkVersion" value="16" />
    <preference name="BackupWebStorage" value="none" />
    <preference name="SplashMaintainAspectRatio" value="true" />
    <preference name="FadeSplashScreenDuration" value="300" />
    <preference name="SplashShowOnlyFirstTime" value="false" />
    <preference name="CordovaWebViewEngine" value="CDVWKWebViewEngine" />
    <plugin name="cc.fovea.cordova.purchase" spec="^7.1.0">
        <variable name="BILLING_KEY" value="*****" />
    </plugin>
    <feature name="CDVWKWebViewEngine">
        <param name="ios-package" value="CDVWKWebViewEngine" />
    </feature>
    <feature name="StatusBar">
        <param name="ios-package" onload="true" value="CDVStatusBar" />
    </feature>
    <preference name="SplashScreen" value="screen" />
    <preference name="SplashScreenDelay" value="3000" />
    <plugin name="cordova-plugin-camera" spec="^3.0.0">
        <variable name="CAMERA_USAGE_DESCRIPTION" value="To Share Photos on *" />
        <variable name="PHOTOLIBRARY_USAGE_DESCRIPTION" value="To Share Photos on *" />
    </plugin>
    <plugin name="cordova-plugin-device" spec="^1.1.7" />
    <plugin name="cordova-plugin-file-transfer" spec="^1.7.0" />
    <plugin name="cordova-plugin-splashscreen" spec="^4.1.0" />
    <plugin name="cordova-plugin-statusbar" spec="^2.3.0" />
    <plugin name="cordova-sqlite-storage" spec="^2.1.4" />
    <plugin name="cordova-plugin-x-socialsharing" spec="5.4.1" />
    <plugin name="cordova-plugin-ionic-keyboard" spec="2.1.3" />
    <plugin name="cc.fovea.cordova.purchase" spec="^7.2.6" />
    <plugin name="cordova-plugin-inappbrowser" spec="3.0.0" />
    <plugin name="cordova-plugin-ionic-webview" spec="^3.1.2">
        <variable name="ANDROID_SUPPORT_ANNOTATIONS_VERSION" value="27.+" />
    </plugin>
    <plugin name="cordova-plugin-whitelist" spec="^1.3.3" />
    <plugin name="cordova-plugin-facebook4" spec="4.2.0">
        <variable name="APP_ID" value="*" />
        <variable name="APP_NAME" value="*" />
        <variable name="FACEBOOK_HYBRID_APP_EVENTS" value="false" />
        <variable name="FACEBOOK_ANDROID_SDK_VERSION" value="4.40.0" />
    </plugin>
    <engine name="ios" spec="4.5.5" />
    <engine name="android" spec="^7.1.4" />
</widget>

and ionic info:

Ionic:

   ionic (Ionic CLI)  : 4.10.3 (/usr/local/lib/node_modules/ionic)
   Ionic Framework    : ionic-angular 3.9.2
   @ionic/app-scripts : 3.2.0

Cordova:

   cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
   Cordova Platforms     : android 7.1.4, ios 4.5.5
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 3.1.2, (and 10 other plugins)

System:

   Android SDK Tools : 26.1.1 (/Users/Library/Android/sdk/)
   NodeJS            : v9.11.1 (/usr/local/Cellar/node/9.11.1/bin/node)
   npm               : 5.10.0
   OS                : macOS Mojave
   Xcode             : Xcode 10.1 Build version 10B61