Hallo 
@worried-shampoo-21760 , make sure your upstream DNS resolves and set that ip in the "Default Ext Client DNS" in your Network holding your EgressGW Node.
Your EgressGW node should have 0.0.0.0/0 range set and the correct interface, mine was "tvnc", the Network name i'm using.
Now you need to recreate the Ext-Clients configuration for each Ingress Node. That's it ! fire up the new ExtClient.conf file and you should be able to exit to the Internet thru your EgressGW.
you can verify with :
http://portquiz.net
http://checkip.dyndns.org
HTH.