Apple is currently in the process of blocking the SAM unlock, reports MuscleNerd. If you need to unlock a SIM or backup your unlock ticket do it now!
Looks like Apple's currently fixing their activation servers. But the good news is that previous tickets gotten via SAM trick still work.
what it boils down to is an incorrect assumption on the part of the ticket server, which is why it was so quick to fix
for the next few hours, trying SAM on new SIMs will probably be hit or miss, but eventually it will be all "miss"