Two Factor Authentication on Mac in system preferences, iclouud

Hi, can someone help please.

On my Mac, I can't access iCloud account details, when i click on it...it comes up with my iCloud account, name and description to which I click 'ok' then it says 'enter password' which I do, but then it tells me I need two factor authentication, my phone goes off with a message and asks me if I want to allow, then it gives me a code, but on the Mac there is no box popping up to enter that code into!!??

Can someone please help me?

Thanks Jonathan