I can run game in Unity Editor only once

I can run game in Unity Editor only once.
Second time I run game then game visually freezes but it calls void Update() methods.
I do not get any error message.
SkyBox disappear.
If I restart Unity then game run well when started first time.
I am on Mac.
I can run game on mobile phone.

I was wrong concern SkyBox. It was unexpected camera angle.

It was not responding on touch events.

When I checked “Force Module Active” in EventSystem then it started to work.