How to unlock an Iphone

trying to unlock a phone with no number or account, the phone is a very old phone I previously used years ago

https://www.att.com/deviceunlock/#/

Hi @gurgur!

I definitely apologize for that happening on the device request!

Was the phone purchased through AT&T directly or a third party such as Amazon, eBay, Best Buy, etc.? If it was, it will register as not a consumer device since it is not locked to AT&T’s network.

To get a better look into this for you, I will be sending you a private message so we can gather a bit more information. Be on the lookout for that message in your inbox

Have an awesome week! Take care.

Kevin, AT&T Community Specialist

I have the instructions and have been approved to unlock my iPhone5S. My reason for unlocking is so that when I travel to Europe and can swap in a Pay-as-you-go SIM card. And when I return i will want to put my ATT SIM card back in and continue to use as normal. Will I lose anything if I do a full back up, reset phone and then reinsert my current card? Will all things look the same? And when I do insert the European card, will I still need to go through a resetting process? 
Thank you for your help.

Unlocking does not effect your data.  (You should backup regularly anyway)

However, the best way to unlock, is to use your ATT SIM card, backup, erase and restore.  I backup to a computer, manually erase the phone, then restore from computer backup.  That way you can be sure it is unlocked for another carrier.  

It took doing the backup erase restore twice with ATT SIM card before I got the "congratulations!  Your iPhone is unlocked".  This isn't something you want to do on vacation or business trip.

I have just gone through this process. The phone reset and the back up restored from computer, but I never got the message "your iPhone is unlocked". Is that what you mean that I may need to do it again until I get that message?

Thank you for your help.

I contacted ATT via chat and they told me my iphone was unlocked. Solved!

Hi,

I paid off 3 iphone 6's that I purchased on the next plan in April 2016. It shows that all are eligible for an unlock request so I submitted requests for a total of 4 phones that are on my plan. Unfortunately, I have one phone that I am being denied for an unclock request. It was purchased 2 months before the other phones .

This is the message that I keep recieving: "

Because of certain AT&Tguidelines, we were not able to unlock your device." 

Customer service offered no help but simply said to wait a couple of days. The other requests were submitted on August 3. I have tried again today August 6 and am recieving the same message. I appreciate any assistance that you can offer.

HI... I tried to unlock my iphone 4s,but att answer was:

 Because of certain AT&Tguidelines, we were not able to unlock your device.

Can anyone help me? Ibougt this phone on ebay. I live in Georgia, Tbilisi.