How to change server URL in mobile application

Install & Config
#1

I changed the default URL in Mainactivity.java
private void setJitsiMeetConferenceDefaultOptions() {

    URL serverURL;
    try {
        serverURL = new URL("https://xxx.domain.com");
    } catch (MalformedURLException e) {
        e.printStackTrace();
        throw new RuntimeException("Invalid server URL!");
    }
    JitsiMeetConferenceOptions defaultOptions
         = new JitsiMeetConferenceOptions.Builder()
        .setWelcomePageEnabled(true)
        .setServerURL(serverURL)
        .setFeatureFlag("server-url-change.enabled", !configurationByRestrictions)
        .build();
    JitsiMeet.setDefaultConferenceOptions(defaultOptions);
}

but the server URL not changed. It still https://meet.jit.si