Installation issues no power

Hello. Need assistance. I have tried to set up my doorbell camera but cannot get it to power up after installation. I have followed all the steps. Two things I’m thinking might be the issue.

One is that my existing doorbell chime transformer is 10-16 v

Second is that I have the back door wired as well. In the instructions and every video I can find no one has the “rear” terminal wired. I tried using both provided “jumpers” to connect all three terminals. Nothing is working.

Any advice would be appreciated.

Thank you