Ring Mailbox Sensor false alarms

I have installed the mailbox sensor in the back of my mailbox. It notifies me of motion when I open the mailbox door and after closing the door it will notify that it has stopped detecting motion. I keep getting motion notifications all night long and no one is in my mailbox. Anyone else having issues? I was thinking it was sensing the mailbox moving with the wind or when cars drive by or that it can see past the door on the plastic mailbox that doesn't seal 100%. Thanks