Screen not properly working after replacement

Hello Peeps!

I replaced my cracked screen 2 days ago (was not my first 5s screen replacement) and it worked fine for about 1 1/2 hour.

Suddenly the screen went black and when pressing home or power button the screen only slightly lights up (reaaaaally slightly).

Checked if all cables are connected properly and did all software stuff i know about!

iPhone is clearly on as it vibrates when connected to the charger or when switching the mute/unmute button!

Any suggestions or anyone had the same problem who found a solution?

Thanks in advance!