Cannot manage other PC users through "Your family"

I've just upgraded from Windows 8.1, where all the user accounts on the PC were local accounts, but "Family Safety" allowed me to manage them all. In Windows 10, they have to be Microsoft accounts, rather than local ones -- which itself seems unnecessary to me.

Anyhow, I've converted all the family's PC accounts to Microsoft online accounts, rather than local ones, and verified their e-mail addresses. Then, from my account, in the "Accounts"->"Family and other users" Control panel settings, I've sent "invitations" from my account to "join the family", and I've accepted those invitations from all the other family members' accounts.

But, back in the Windows10 "Accounts"->"Family and other users" Control panel settings in my account, they're all still showing as "Pending", and at the "Your family" section of the Microsoft website (https://account.microsoft.com/family#/), they're all still showing as "Invitation sent".

Why? Have I missed a step? Or has Microsoft totally broken the ability to manage other users' PC access (that worked perfectly well with local accounts in Windows 8.1)...?

So I solved it.

I had previously used my default browser (Firefox) to accept the Invitations to "join the family". I tried again, but this time opening the links using Edge.

Guess what? It worked immediately.

I thought Microsoft had been told off by various courts for tying the operation of the O/S too closely to their own browser. And yet here we go again. If you want to use "Family Safety", you have to set it up using Microsoft's browser, not a competitor product.

MBiddiscombe said:

So I solved it.

I had previously used my default browser (Firefox) to accept the Invitations to "join the family". I tried again, but this time opening the links using Edge.

Guess what? It worked immediately.

I thought Microsoft had been told off by various courts for tying the operation of the O/S too closely to their own browser. And yet here we go again. If you want to use "Family Safety", you have to set it up using Microsoft's browser, not a competitor product.

I've noticed this as well. Everytime Chrome is the default browser (in my experience), things never work quite the way they're supposed to. I also tried to use the Mail program to update my Gmail and it didn't work, yet when I added my Outlook account everything was pristine.