We've an article that can help resolve most issues with iCloud Keychain.
I'm not receiving the verification code via SMS.
- Make sure that you have a good cellular network connection on your phone.
- Check that your phone number is one that can receive SMS messages. You can do this by having someone send you a text message.
- Check that you have the correct phone number associated with your account:
- Devices using iOS 7.0.3 or later: Tap Settings > iCloud > Account, then tap Keychain. Check that the phone number listed under Verification Number is correct. If not, enter another phone number.
- Macs using OS X Mavericks v10.9 or later: Choose Apple () menu > System Preferences. Click iCloud, then click Account Details. Check that the phone number listed under Verification number is correct. If not, enter another phone number.
- Check Apple System Status to see if there is currently a service outage affecting iCloud Keychain.
- If you do not have access to a device that has iCloud Keychain enabled, you can contact Apple Support and verify your identity for help completing iCloud Keychain setup.
That's all very nice, but these instructions simply don't match up to the reality of the devices. I tap Settings-iCloud-Account-Keychain on my iPhone (iOS 7.0.4) and all I see is an "Approve with Security Code" switch that is turned on. There is no verification phone listed nor any way to add one. I know I did it when I started this process several weeks ago, but with my Google text number seemingly unable to receive I'd like to change to another number and get this done.
Same is true on my Mac. I'd be happy to change that verification phone, but in don't see to be able to. Help! I'm caught in an infinite recursion!