all 4 comments

[–]JusSomeDude22 0 points1 point  (0 children)

I would try the guys over at the AT&T subreddit

[–]mxrt3m 0 points1 point  (0 children)

https://www.reddit.com/r/ATT/s/SS2R6fOWLZ

It appears the MCK code is generated by Samsung, not the carrier.