@Der Hochstapler thanks for the solution.
but in IONIC 4 some customization in project config.xml work for me
Add a line in Widget tag
<widget id="com.my.awesomeapp" version="1.0.0"
xmlns="http://www.w3.org/ns/widgets"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:cdv="http://cordova.apache.org/ns/1.0">
after this, in the Platform tag for android customize some lines check below
add usesCleartextTraffic=true after networkSecurityConfig and resource-file tags
<platform name="android">
<edit-config file="app/src/main/AndroidManifest.xml" mode="merge" target="/manifest/application" xmlns:android="http://schemas.android.com/apk/res/android">
<application android:networkSecurityConfig="@xml/network_security_config" />
</edit-config>
<resource-file src="resources/android/xml/network_security_config.xml" target="app/src/main/res/xml/network_security_config.xml" />
<edit-config file="AndroidManifest.xml" mode="merge" target="/manifest/application">
<application android:usesCleartextTraffic="true" />
</edit-config>
</platform>