Minecraft installed under parent account, will work for 1 child but not the other

Hello there, it sounds like you're trying to game share to more than one account, which is not how game sharing is intended to work.

The long and short of it is, if you buy the game on your account and you log into someone else's device to install and play it there, and allow them to access it, you can only do that with one other device/account at a time. Either one other PC or one other console.

The explainer:

Game sharing allows a user to login somewhere else and install the game. This allows other users to then play that base game without any additional work needed. Note that DLC and other add-ons are not playable in this case.

So that's why it's not working on the second account.

Overall solution:

You should purchase the games individually for each child on their account. As the parent, you can provide a pre-paid allowance through the Family options, or alternatively buy each of them a gift card and redeem them on each account so that you can purchase the game for each of them separately.

I hope this helps clarify. If it hasn't been too long, I recommend you submit for a refund for the copy of the game on your account.

You have registered your "main account" as child account (under 18+ of age) this is why you are not able to play online and Mojang support suggested you to set up a different account

Unless your parental account gives permission your child account will not be able to play other realms in Minecraft

I checked the issue with Microsoft Account tech support, and they sent me back here.

On their end everything work as expected: my parent account and child account are properly connected, I see the child account under the parent account, can set the permissions for the child account.

But apparently the parent-child accounts relations are not propagated correctly to the Xbox LIVE system.

well under the parental email

goto manage child accounts

remove it

then add it again under the new account

all child accounts must have a parental account till it matures

Alright so I figured it out.

Attempting to add the child account didn't work as it said the child account was already apart of a group. I learned through talking with my parent that there was a separate email. Basically two sets of parent and child accounts. I was able to get into the *other* parent account and have changed the child account's age from there. I haven't tested if this will allow me to actually play multiplayer/realms on Minecraft yet, but if I don't reply again to this thread, any future viewers can assume it did in fact work and all is well.

Thank you again for all your help!