Front and Back camera don't work

I have a motorola MB860 phone and after a repair both frontal and back cameras don't work.

When I touch the camera button the camera app opens but the screen is black. If I touch the shutter button it looks like the picture is taken, but it doesn't save the picture. The flash doesn't work. And frontal camera is the same thing. Only a black screen. The camera app doesn't force close or anything. It opens normally, but cameras don't work.

I tried updating the software of the phone and still the same issue with both cameras.

Do you know if it is a hardware problem? Speakers, microphone, and volume keys work fine. I know they are connected to the flex cable of the front and back camera. So what does that mean?

I just need to know if I need to change the parts or maybe there is something else I can try to fix it.

Thank you