The cause: This occurs to the API versions 28 and up because they no longer support HTTP requests; you must change if you still wish to accept HTTP or localhost requests.

Solution: This error can be solved by these below steps:

Step 1:

In Android Manifiest, in tag application add:

android:usesCleartextTraffic="true"
android:networkSecurityConfig="@xml/network_security_config"

Step 2:

Create in folder app\src\main\res\xml this file network_security_config.xml and write this:

<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<base-config cleartextTrafficPermitted="true" />
</network-security-config>

Step 3:
inside tag application add this tag:

<uses-library android:name="org.apache.http.legacy" android:required="false"/>