Can’t approve my iPad

I turn on my two authentication thing and now both of my iPad and phone need to update Apple ID setting thing l. It ask me to put in my password for my Apple ID and my iPad password, which I did put it in correctly. Then it ask me to approve my IPad from a different device by signing in to iCloud to approve the iPad, but nothing show up on my phone to approve my iPad. This goes the same for my phone. My iPad is IOS 12.4 so I can’t turn off the two authentication.