Zend certified PHP/Magento developer

Cannot fetch GPG public keys with Kleopatra in Windows

In Kleopatra (Windows), I have the following key server
Kleopatra Key Server

When I try to fetch the GPG public key of XUbuntu (843938DF228D22F7B3742BC0D94AA3F0EFE21092) using Lookup on Server functionality, Kleopatra doesn’t return anything
enter image description here

I’ve tried the following servers but nothing changed

  1. hkp://keys.gnupg.net
  2. keys.gnupg.net
  3. http://gpg-keyserver.de

How should I debug this problem? Is there anything I’m missing here?