Moving from Straight Talk to Ting, unlocked Fire Phone

Hey guys, I hope I'm in the right place here. I'm trying to move my Amazon Fire Phone (purchased unlocked) from Straight Talk to Ting. When I put the SIM in and boot the phone it's asking me for a PUK. I have the Ting card with the PUK... but it's not working :( Do I need to request a new SIM?

Here's the kicker though - I put it in my wife's phone who also is on ST (we both signed these phones up at the same time), and the Ting SIM works fine in her phone without issue. What gives?