Parking on private property—is it actually illegal?

Hi there,
I was hoping someone could help me clarify something.

I parked my car right in front of a garage on private property, and I had full permission from the owner to be there.

Despite that, the police issued me a citation based on local parking ordinances.

I know I can't officially appeal until the actual fine is issued, but does anyone know if I have a legitimate case here? Since the vehicle was on private property rather than a public street, does that change things?

First comes the GOP, then comes the whining.
You're gonna sit there and claim the garage owner gave you the green light, and then try to drag him in as a witness too.