I've payed off my S8+ and have been told by Sprint it's showing unlocked on their end but I still get invalid sim when I insert T Mobile SIM. Also getting UICC unlock internal error 407.
tends to help if you add just a tad bit of info on what you have going on and what all has been attempted so far to try and fix it...mainly so the agent that pops in to assist doesnt run you through the same gauntlet of troubleshooting.
You need to go to the store and have them update the IMEI and maybe a new sim card onto your account under the phone number you are using. This usually happens when you pop a sim out and put into a different phone without updating Sprint.
I've also been having this problem with my note 10+. I'm being told that its unlocked by sprint but when I try to use my Verizon sim my phone tells me to contact sprint to unlock.
Please know that Sprint devices aren't guaranteed to work on another carriers network. I'm going to send you a private message for more information.
I'm having the same problem as everyone else. I've got a Galaxy S8+ that was on Sprint's network for a year, and has been deactivated for a year. I wanted to unlock it, so two days ago I called Sprint support, while the phone was connected to wifi, with the Sprint SIM card installed. They (very helpfully) worked through it with me and sent an unlock code. Unfortunately, I still receive the "update could not be completed Internal Error 407" message whenever I try to update PRL, Profile, or UICC. Thanks!