Adding a child never goes past "Checking Info"

[areseven]

I have a Fitbit Ace 2 that I have reset and I'm trying to get my daughter set up. As in the instructions, I've gone to the Fitbit app on my iPhone, selected Add Child, and selected my daughter's account, which is part of my Google Family account. Her account appears below "Select a child from your family group on Google". 

When I select her account, though, it goes to a screen that says "Checking info...This could take about a minute". However, it never progresses past that screen, no matter how long I wait (I have let it go for hours, even). I've tried restarting both the Fitbit app and my iPhone, but it never gets past that screen. I've tried both on my home network and on my wireless signal.

My daughter's account is supervised with Google Family.

What can I do here to get her account added to my family in the Fitbit app so that I can get the Ace 2 set up?

[JohnnyRow]

No idea if this will help but it's a post that just went up today.  Can't tell if it's something they just fixed, or just a new instruction post.
I don't use family accounts so I can't judge.

https://community.fitbit.com/t5/The-Pulse-Fitbit-Community-Blog/How-to-set-up-the-Fitbit-Ace-tracker...

[brewchester]

So I'm not sure if you got this to work, however, I was having the same problem with my 13 year old trying to use the app for her Charge 6 we just got her. I got the message that it couldn't connect because of the supervision so I removed her account from family link, set up her account in fitbit, then re-enabled supervision again. So far so good and might be worth a shot. I have the Ace 3 on order for my son who is 9, so I'm hoping it's the same result because why else would we get the devices for them if we can't manage them. Good luck.