Replacement screen glitches after android startup-logo

Hi there,

Today I tried replacing my cracked screen with one I bought on Ebay (screen + frame). Using a YouTube video installation went fine. I closed the phone back up and Lord and behold, the android startup animation pops up.

My happiness did not last long because right after the startup animation was done, the homescreen flickered for one ms and then went black. The colours that I could see were messed up aswell..

I opened the phone again and made sure all connectors were placed correctly, and they were.

Did I do something wrong here or did I receive a faulty screen? I find it particularly strange that the startup sequence has no errors whatsoever.

I hope you guys can be of some help to me!

Thanks

Ps. I made a video to showcase the problem: https://gfycat.com/FaroffFlusteredBantam...