This may be permission related. Try removing and re-adding the cordova-plugin-whitelist:
cordova plugin add cordova-plugin-whitelist
If that isn’t working, then it would be worth checking the Content Security Policy (does it include permission to call that target URL) and config.xml setting for allow-navigation.
Is this impacting all HTTP calls to that server? It may also be worth checking / sharing the AndroidManifest.xml file (should include ).
Related post Status Code:404 Not Found (from disk cache) on Android device only