ICloud Keychain won't accept pass code

I Am trying to set up iCloud Keychain on My iPad and iPhone. I have received my iCloud Keychain verification code on my phone and entered it correctly on my iPad. . I've done this twice. I continue to receive a message on my pad after entering it that I'm entering the code number incorrectly. I am not entering it incorrectly. After the third attempt I stopped trying. Does anyone know what I may be doing wrong?