iPhone Bootloop after new LCD

Hello everybody,

I wanted to change due to a display damage (glass break) the LCD of the iPhones and ordered one on eBay. Mobile phone opened, battery disconnected, display changed and mobile phone adjusted to look to whether pixel errors or similar. (LCD was not pre-mounted)

The mobile phone Bootlooped 5-6x until it finally goes and as soon as it is on it depends .. I tip on any app and it opens only after 10 seconds. While I can not do anything, its frozen. As soon as I am in the app everything runs flawless ..

Edit: Original display reinstalled as well as mobile phone with iTunes reset - same problem

Looking forward to every tip. Thanks in advance!