iPhone 7 stuck on Apple logo when Chargingport Ribboncable is in place

Hello Community, i could cry, after changing the whole Housing from my iPhone 7, if i click the ribbon connector into the Mainboard, the Phone shuts down and keeps bootlooping, when i disconnect it, it does actually boot up, but no signal, sound and vibration, so… i‘ve replaced the charging flexcable, did a before built in and after, before i‘ve built it in, it actually charged etc. after it was in there, i could again not start it, im honestly so sad, its just rediculous, when i plug in the old flexcable (without it being srewed in and stuff) it will start and charge…. does anybody have clue? i would greatly appreciate it!

sorry for my bad english, but im so upset about this!