Cannot sign in on computer

As of recently, I cannot sign in on my computer with my iCloud password. It always asks me for my password. I enter it. Then I get the alert on my phone that I am trying to sign in. I click ok, and then I get the verification code. But, on my mac, it never pops up. I just get another pop up of enter your password. And I do it again, and the same thing happens. It won't let me sign on. How can I fix this?