Ionic 4 Http request status 0

Hello,
When I use http.get(‘myurl’).subscribe(…) i got response like this:
HttpErrorResponse {headers: HttpHeaders, status: 0, statusText: "Unknown Error", url: "....", ok: false, ...}

Normaly when i first installed ionic everything works fine. But when I have changed the config.xml and network_security_config.xml this problem arrived.

my config.xml code that i added:

<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" android:usesCleartextTraffic="true" />
        </edit-config>

my network_security_config.xml code that I added:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
    <base-config cleartextTrafficPermitted="true">
        <trust-anchors>
            <certificates src="system"/>
        </trust-anchors>
    </base-config>

    <domain-config cleartextTrafficPermitted="true">
        <domain includeSubdomains="true">localhost</domain>
    </domain-config>
</network-security-config>

And now I am facing that problem. How can I solve this problem but not to lose my app’s functionalities?