Choose ‘'Development’' or ‘'Debug’' as your ‘'Build Configuration’' before Packaging your app from UE to generate Logs and allow our system to capture them.

See how to Select a Build Configuration here Select a Build Configuration to Package your UE Project

Go to: Control Panel → Edit → Developer Options → Print UE4 Log in Browser Console → Save.

Make sure your ADBLOCK is disabled or it will block the Logs from being generated to the browser.