Q: Ask to buy stopped working from macbook air

My son has an iPad and Macbook air. To download apps from the App Store we use the family approval feature, where he has to ask to buy and I get a notification on my iPhone. This is working perfectly from my son's iPAD, but recently stopped working from my son's macbook air. He is logged in under the same ID on both devices, but one works and one doesn't work. When he asks to buy from the macbook, I get the notification on my phone, but when I click on the notification it hangs up on a "loading" screen, so I can't ever see the details of the request to decline or approve. This used to work flawlessly, and neither my son's macbook nor my phone has an updated OS since it worked, so a change in OS can't explain why it stopped working. The only thing that seems correlated with when this stopped working is that both of us traveled abroad with my son's macbook and my phone (but left his iPad at home). He did try to ask to buy while we were abroad.

I have rebooted both devices and logged out and back in.