4.21 Multi-User Viewer Template - No Servers Found

Hi,

Not sure what I did wrong, my packaged game (built using 4.21.2 Multi-User Viewer Template, Shipping & Development Build) can’t see host anymore and always show ‘No Servers Found’ message. It works when I manually enter IP address.

There was no change in my networks and this problem happens even to new blank Multi-User Viewer Template project.
It used to works fine btw. Totally clueless what happened here.

If anyone have any idea what could possibly the cause or any suggestion, kindly advise please.
Thanks in advance!