2fa interfering with App Store sign-in

I'm trying to sign into the App Store to install an already-purchased app onto my Air (is already installed on my iMac). The Store requests I sign in, I enter my AppleID and password, and the Store pushes a 2fa verification code to my phone. However, the Store doesn't present a new window in which to enter the code (unlike, say, when signing into iCloud.com), so the sign-in can't complete.

Since I can't disable 2fa, how can I manage this sign-in problem? Thanks.