Ionic 4 Android 9.0 Login failed - ionic-framework

Question

Android 9.0 not login but below 9.0 works fine
generally my code works fine on marshmallow
when I build my app android pie it is not working.
My code here below I can not understand this problem.
AndroidManifest.xml code
**<?xml version='1.0' encoding='utf-8'?>
<manifest android:hardwareAccelerated="true" android:versionCode="1" android:versionName="0.0.1" package="io.ionic.starter" xmlns:android="http://schemas.android.com/apk/res/android">
<supports-screens android:anyDensity="true" android:largeScreens="true" android:normalScreens="true" android:resizeable="true" android:smallScreens="true" android:xlargeScreens="true" />
<uses-permission android:name="android.permission.INTERNET" />
<application android:hardwareAccelerated="true" android:icon="#mipmap/ic_launcher" android:label="#string/app_name" android:networkSecurityConfig="#xml/network_security_config" android:supportsRtl="true" android:usesCleartextTraffic="true">
<activity android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|smallestScreenSize|screenLayout|uiMode" android:label="#string/activity_name" android:launchMode="singleTop" android:name="MainActivity" android:theme="#android:style/Theme.DeviceDefault.NoActionBar" android:windowSoftInputMode="adjustResize">
<intent-filter android:label="#string/launcher_name">
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider android:authorities="${applicationId}.provider" android:exported="false" android:grantUriPermissions="true" android:name="org.apache.cordova.camera.FileProvider">
<meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="#xml/camera_provider_paths" />
</provider>
</application>
<uses-sdk android:minSdkVersion="19" android:targetSdkVersion="28" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
</manifest>**
**Ionic Info : Ionic:**
Ionic CLI : 5.2.8 (C:\Users\Dev\AppData\Roaming\npm\node_modules\ionic)
Ionic Framework : #ionic/angular 4.11.1
#angular-devkit/build-angular : 0.801.3
#angular-devkit/schematics : 8.1.3
#angular/cli : 8.1.3
#ionic/angular-toolkit : 2.0.0
Cordova:
Cordova CLI : 9.0.0 (cordova-lib#9.0.1)
Cordova Platforms : android 8.1.0
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 4.1.2, (and 12 other plugins)
Utility:
cordova-res : 0.6.0
native-run : 0.2.8
System:
Android SDK Tools : 26.1.1 (C:\Users\Dev\AppData\Local\Android\Sdk)
NodeJS : v10.13.0 (C:\Program Files\nodejs\node.exe)
npm : 6.11.3
OS : Windows 10
when login Android 9 show this problem only
HttpErrorResponse {headers: HttpHeaders, status: 0, statusText:
"Unknown Error", url: "http://example.com//access-token", ok: false, …}
error: ProgressEvent {isTrusted: true, lengthComputable: false, loaded: 0, total: 0, type: "error", …}
headers: HttpHeaders {normalizedNames: Map(0), lazyUpdate: null, headers: Map(0)}
message: "Http failure response for http://example.com//access-token: 0 Unknown Error"
name: "HttpErrorResponse"
ok: false
status: 0
statusText: "Unknown Error"
url: "http://example.com//access-token"

Answer 1

Since you didn't post your code part, here are some possible solution.
In most of the cases in ionic, Status code 0 usually indicates a CORS failure. Please check if CORS is enabled or not.
Second most possible cause is SSL certification.
Android platform level 28 disables cleartext network communications by default.
https://developer.android.com/training/articles/security-config.html#CleartextTrafficPermitted
https://stackoverflow.com/a/56178196/7803492

Answer 2

Step 1.
Open AndroidManifest.xml from [yourProject]/platform/android/app/src/main/AndroidManifest.xml
Setp 2.
Add this line to that file
android:usesCleartextTraffic="true"
step3. Save the file and rebuild the apk again