Q: Still unable to turn on two-factor authentication even when the Set-up button is present

Then how to enable 2FA? Family has 3 Apple IDs, only mine has 2FA enabled, the other 2 IDs don't even have 'enable 2FA' button in iCloud/Security under iOS 9.3 (before iOS 9.3, there is '2FA' button but it prompted error 2FA not available for this Apple ID).

They never have Two-Steps enabled before, nothing to be turned off at appleid web site.

OK I managed to enable one more Apple ID, which didn't have security questions setup, maybe Apple treated that as 'incomplete' Apple ID account so it refused to continue rest of functions. Once I filled up security questions, I have 2FA-enable option immediately.

But, the 3rd Apple ID, Child's Apple ID, is still unable to have 2FA-enable option, even it has security questions setup already.

someone tested and confirmed kids under 13 don't have two-step or two-factor options listed in their appleid web page. i think it is because of the federal regulation, that kids under 13 aren't supposed to put information on the net.

change birthday will work.

There is nothing stated on any Apple website that children are unable to have 2FA. An iPod touch or iPad can be a trusted device, so they don't even have to have a phone. And COPP does not prevent them them from having an online presence, it just requires parental consent to set them up online.

If their profile doesn't show a compatible device, that may be why you're not seeing 2FA for them.

LACAllen wrote:

 

There is nothing stated on any Apple website that children are unable to have 2FA. An iPod touch or iPad can be a trusted device, so they don't even have to have a phone. And COPP does not prevent them them from having an online presence, it just requires parental consent to set them up online.

 

If their profile doesn't show a compatible device, that may be why you're not seeing 2FA for them.

 

iPhone 6s, iOS 9.3

appleid web also mentioned: Your correct birth date is required to enable some Apple services.

Someone helped to test and confirm:

Two-Factor Authentication is not available for Child's Apple ID?

In fact, it is mentioned in iCloud T&C http://www.apple.com/legal/internet-services/icloud/en/terms.html

The Service is only available to individuals aged 13 years or older

I think that is referring to the iCloud service, which is unrelated to an Apple ID itself.

Kids under 13 are absolutely able to have an Apple ID. In fact they also mention iCloud services specifically as being available to a child under 13 on this page... so there appears to be a contradiction here.

Family Sharing and Apple ID for your child - Apple Support

2FA is a iCloud service so it follows T&C.

not all iCloud services are available for all age, this is also mentioned when you try to change date of birth on appleid web site.

Great to see this finally available for everyone.

Love how instantly the codes get pushed to trusted devices.

Had to turn off 2 step first then activated 2 factor via a device as it does not seem to make it available at appleID.com.

I still cannot see 2FA option on neither of my devices, even though all of them are eligible (iOS9 or OSX10.11) for it. I have all security questions filled and credit card added, the birth date is also correct. I tried to sign out of the iCloud on one of the devices, however, it didn't help. Any more suggestions?

Thanks.

Do you have 2 Step Verification enabled right now?

If so, you need to go back to regular security first, then  2FA should be available. You can't directly go from 2SV to 2FA.

No it is turned off. Still cannot see an option to turn on 2FA on my iPhone.

If you haven't already, I would call Apple Support. They have a more options to help you the we do here.

As of about three weeks ago (somewhere around March 23, 2016) Apple's 2-Factor Authentication became available for me.

I set up a reminder to check availability every two weeks and one day it worked.

If you are still unable to turn off 2 factor authentication, you have to select completely new security questions.  If you do not, you get stuck in a loop.  This worked for me.