PN532 - NFC Trouble

Hello World (this is my first forum post so I thought that was fitting.)

Completely new to Arduino. Picked it up when a raspberry pi project failed.

I am trying to duplicate my apartment building's key fobs and thought this would be a good first project.
Please note, I am not a criminal... i am doing this because my building charges crazy prices for extra fobs and I need them because I need one for me, one for my wife, one for each of my dog walkers (2) one for my baby sitter, one in my friend's place for emergencies... and, low and behold, my wife lost hers and my dog walker dropped his and broke it.

I bought an Uno and PN523 (this modelL NFC Shield - Elecrow)
I've followed all the instructions and can read the fob that came with the PN532, but I cannot read my building's fob.

Anyone know why that is?

Thanks in advance!

Because the fob is designed so it cannot be copied.

Or it may operate on a different frequency/protocol.