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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.

Can you please sign in to https://account.xbox.com/settings and make sure that the following setting is all set to "Allow"?

After that, try to buy Minecraft realm again.

Can you try power cycling the console by holding the power button on it for 10 seconds until it shuts down?

Hey there K Reeky -

Sadly, we're unable to assist with actions taken by the Enforcement team here on the forums. The Enforcement team does not use the forums, so they will not be able to respond here, unfortunately. Please reach out to them at http://enforcement.xbox.com/ to
submit a new case review if necessary.

Thanks for understanding! If you have any additional Xbox support questions, please let us know!

Access to the online is usually run by the developer, not xbox live. More than likely your ea account I believe with fifa has to be reactivated with some permissions or there is an update. Log on from your computer to ea and update permissions and account
information

So I am going to ask a few questions that seem basic but knowing the answers will help us with understanding possible solutions to your issue.

First off is your Xbox Live subscription still active? If you run out of Xbox Live Gold time then you become Silver again and can't play online.

Second, did you buy Fifa 15 or did someone else buy it and you're on the same console as them? If someone else bought Fifa 15 and the Xbox you're on is their home Xbox then you can play their games, but if they changed their home Xbox you'll lose access
to all of their games, even if the game is still installed on your Xbox.

Your answers will help give me and others an idea of what we could be looking at and what advice to offer in order to help you.