Xbox gold sharing is not working on both my son's xboxs

please help. I have recently bought my youngest an xbox one S. My oldest already has an xbox one and an xbox live gold account. Xbox online confirms you can share a gold account within the house hold. I have watched the tutorial for setting up xbox B as
xbox A's home box and vise versa but it doesn't seem to work properly.

I am able to log into gold on Xbox B using the xbox A account. But then can't log into gold on either xbox A or B using account B.

Please can some one help me before I pull out what little remaining hair I have. Thank you In advance.

:)

 

Xbox backwards compatibility issue

I've had my own account as my home xbox for a while now and I could play all my backwards compatible games on Xbox live with accounts that didn't have gold. No problem there. The problem is that my friend and I recently made eachothers accounts our home
xboxs and now I cant play backwards compatible games on multiplayer with accounts that don't have gold. How is it that all of a sudden I cant play online even though both xbox home accounts have xbox gold and both are gold sharing. It's just on backwards compatible
games btw

 

Playing 2 Xboxes at the same time, in the same home.

If both Xbox consoles are
signing into the same gamertag/account at once, one session will automatically get signed out. I suggest creating an new account for your son.

If you have a digital game library and an active Gold subscription, you can share both of those with your son

using the "Gold/Game-sharing" feature. A recommended way to achieve this is to

set your son's Xbox as the "home" console.