Hello I have a problem. I have a galaxy s7 that is already paid, and I called to sprint to unlock this phone to use any other SIM and then they told me that is already unlock but when I go to 'unlock uicc' that said that my phone is just allows to use sprint sims and when I click there that send me 'internal error 407' and I already try dialing ##72786# and still the same error. Please help.
prior to an agent contacting you in here make sure you have the Sprint sim card back in the phone..that its turned on (and plugged in charging if needed) and that it is connected to wifi.
if Sprints side is showing the phone is unlocked but on your side it is not that usually means one of those things were not in place when the unlock code was sent to the phone. unlocks usually take a couple days to take care of so its more than likely it missed the signal.
once all of this is done post in here that it is taken care of so the agent knows before hand.