After Jailbreak 9.3.3, Cydia won't start

I successfully installed the Pangu Jailbreak via Impactor on my 9.3.3 iOS (5S). When I start the Pangu app it displays: "Jailbreak succeeded!".
But I cannot start Cydia, it immediatly closes after trying to open it. Does anyone have an idea what I can do to run Cydia?
Thanks - Marius