HomeKit Remote Access

I've set up both my Apple TV and iPad as hubs for my home.

My phone works fine for remote access but my wife’s phone will not work.

It will work in the house on wifi but out of house will not work.

I invited her to join and was accepted.

Remote access has been enabled for her on my phone and shows on her phone as well

iCloud is on, TFA is on

I've logged in and out of iCloud on all devices, turned above items on and off, nothing works.

What can be wrong as it doesn’t make sense

Thanks