Front camera not working after screen replacement

Hi. I replaced my Mix 2S cracked screen with a replacement off ebay. The replacement went without a hitch, managed to replace it without breaking anything else or losing anything.

Some time later I realised that the front camera wasn’t working. Figuring I had a loose connection I took it apart again and reseated the camera flex and retried but still i would not work.

I ordered a new camera flex and when it arrived I replaced it and still the issue was the same.

When I open the camera app and press the icon to switch to the front camera it just switches between the two rear cameras which both work perfectly.

There are no errors or anything I can find. Do you have any idea what the problem could be?

I have sent the replacement screen back to see if a new one will make any difference. In the mean time I figured I’d ask on here.

Thanks in advance.