You cannot play on Realms because of how your Microsoft Account is set up.

My microsoft account is not a child account but it still has the same "error message" when I sign in with a child account. (I'm saying error message as in "you cannot play realms because of how your microsoft account
is set up")

It is more of a message than error but it says "You cannot play on realms because of how your microsoft account is set up. Please ensure your online saftey settings allow multiplayer and clubs. See instructions for changing these settings as aka.ms/MCMultiplayerHelp."

Hi, I hope you're doing great out there. I am an Independent advisor and I am here to help you in regard to your concern.

Just a friendly reminder though that to play the Minecraft game online multiplayer on the Xbox console, an Xbox Live Gold subscription is required.

You may need to buy an Xbox Live Gold subscription under your wife's account. Once done, perform a powercycle on the console in that way the console will detect it.

​​​

POWERCYCLE CONSOLE​​​

​​​

1. Turn off your console by holding the Xbox button on the front of the console for approximately 10 seconds. The console will turn off. ​​​

2. Turn your console back on by pressing the Xbox button on the console or the Xbox button on your controller. ​​​

I'm having the exact same issue as OP. I have done everything above mentioned. All my settings are correct. Powercycled, uninstalled and reinstalled, factory reset my xbox as you suggested as well and it still tells me this.

My only difference to OP is I have Xbox Game Pass for Console.

Thank you for contact us! I'm Anderson, an Independent Consultant and a Microsoft user like you.

good afternoon

To change the privacy settings your account must be an adult account, otherwise you will not have access.

see it in your privacy settings:

https://support.xbox.com/en-us/help/family-onli...

if your account is for a child, you need an adult account to link your account and manage your privacy settings