Any updates on this as I am experiencing the same issue?
There are few things to check here:
Follow below steps if you are building the APK file locally
<?xml version="1.0" encoding="utf-8"?>
<manifest ... >
<application android:networkSecurityConfig="@xml/network_security_config"
... >
...
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<base-config cleartextTrafficPermitted="true">
<trust-anchors>
<certificates src="system" />
<certificates src="user" />
</trust-anchors>
</base-config>
</network-security-config>
If you are not building locally then make sure no external API/Service calls are triggered while launching the App in offline mode
Make sure to first synchronize the data before testing offline functionality