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incorrect unlock code from AT&T


New member
Feb 23, 2013

Are you able to get your Lumia 900 unlocked. I am getting the same issue with unlock code provided by AT&T.

Can you please help me how to get it unlocked.


New member
Jan 27, 2012
@ alpinestars1z
If I'm not mistaken you don't need to unlock your phone to use stright talk. Can there be errors as to the database that AT&T people are having. I don't know what they are doing. Nokia has popped up with this smart phone, and AT&T is ruinning the whole thing. Now I can see why there are so many complaints against AT&T service as well as the drop in the market share of NOKIA. They are playing with the customers money.

You're right, I don't. But I wanted to unlock it so I could use it on my overseas vacation.

Nelson K Nelson

New member
May 6, 2013
My HTC Titan says SIM Error every time I try to unlock it with the unlock code and T-Mobile SIM inserted. I haven't been able to find an explanation.

This is my problem, but with the Red NOKIA LUMIA 920. I tried putting in many different T-Mobile SIM cards, and the phone simply won't ask me for the unlock code. (Yes, I do have the unlock code -- AT&T supplied it to me. But there is no way to enter it.) The phone boots up with a T-Mobile SIM and shows, for a moment, the Airplane Mode icon, then up comes an icon of a SIM card with a Circle with Diagonal Bar symbol over it.

Nope, I don't have the original ATT SIM card to insert (bought this phone on Craigslist), but the Lumia 920 seems to resist taking the ##782# command anyway, saying that command is not in its library. Yep, I've factory-reset the phone, and the first time I did that, it locked up in the famous gear-lock position. I was able to rescue from that, and re-factory-reset, twice since, each time to completion. And, no, that's not the problem here, because the problem existed before AND after.

The phone does recognize the T-Mobile SIM and in Settings>About it shows the SIM number AND the T-Mobile phone number -- almost as if it were already unlocked. But the phone says No Service instead of T-Mobile and won't operate. It will check for updated software and do a number of things when WiFi is on. But it won't ask for the unlock code.

I know I am not the only person to experience this -- and I have checked all aspects at both T-Mobile and ATT: No, my IMEI number is not blacklisted with either carrier. Both carriers show clean IMEI.

There was one time where, briefly, after boot-up, and after the Airplane Mode ICON disappeared, I saw T-Mobile appear on the phone tile for a few seconds before the phone went to No Service. So it's almost as if the phone is already unlocked, and checks-in using my T-Mobile active SIM, and then gets an instruction from somewhere to show No Service. Odd.

If you've seen this with a Nokia Lumia 920, please post so it can be solved.

I have started a separate thread for this problem here: http://forums.windowscentral.com/no...-enter-my-valid-att-supplied-unlock-code.html

Last edited:


New member
May 28, 2013
why my lumia 1020 at&t attempts reset each time entering wrong code ( i don't have correct code)
tried several time ,,still 10 attempts remaining

Asvin Peiris

New member
Feb 5, 2013
I'm having the same issue.
I got the code from ATT. Tried entering it, says incorrect code (It is correct though). Then I try entering it again and it says SIM error. After that any number I put doesn't use up an attempt in order for me to finish all my attempts and try the PUK method.

Any solution? Called ATT & Microsoft Mobile, both seem to have no idea. Unlock code is correct (triple checked with ATT)


New member
Nov 16, 2003
Unlocking Lumia 900 -- AT&T SIM/Network Lock Code Is Incorrect - FIXED!

The workaround is this: Enter the incorrect code until you run out of your ten (10) attempts. Then you'll get the *real* network unlock message, with 32 attempts. Enter the same 8-digit code you've been entering, and voila, you're now free to use this on any network!

It worked for me
Kudos to Breex243@xda-developers

This just worked for my ATT Lumia 900. So glad I found this thread... in 2019!!!

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