keychain verification code not working on iPhone

I just got my Macbook op system reset/reinstalled due to software problems. After verifying the keychain on the newly reconfigured mac using the code sent to my iPhone I later got a message oh my iPhone that another device reset the keychain. When I try Approve with security code on the iPhone to activate the keychain I get the verification code on the iPhone and enter it but the verification code process never finishes. What's the problem? Why can't I get keychain to setup again?