Cannot host shooter demo

Dear UT4 community,

We’re trying to play-test the shooter demo in hope of learning about UT4’s networking. Unfortunately, after we compile and run the game launcher, we cannot do anything with it. All the hosting commands become inactive and we couldn’t click on anything.
(It’s the same thing when we play it in editor too.)

Is Anyone experiencing this? Or it would be great if someone could give us some pointer. Thx…

Never mind, you need to click on host or join button again… sorry for this.