Can't use online features in Minecraft on Xbox One

Oddly enough, the issue resolved itself. Don't know what the problem was but thank you anyway. And no, the account is not part of a family group.

I'm Samy an independent advisor. Welcome to the Xbox community. How are you?

Is this account that cannot access the content within a family group? If so, leave the family group, clear your console's MAC and try again.

To clean the MAC follow this path

Settings>general>network settings>advanced settings>alternative MAC address and click clear and restart the console when prompted.

If the problem persists reset the console to factory defaults, you won't lose anything but you will need to log in with your account again. Email and password are required.

Follow this path and select reset keeping games and app.

In 5 to 10 minutes you will finish reconfiguring your console

To reset the console>

Settings> System> Console Info> Reset Console

***Do not reset your console without having your account email and password.***

It seems so, I'm seeing other users report the same thing that out of nowhere are not able to access these service.

I'm having issues again. I can see the Minecraft Marketplace but it gives me an error message when opening it. I don't have access to Realms, servers, or skins again. Is this an issue with Mojang/Microsoft's servers or something?

It's good to hear it. It can sometimes take a while for updates to take effect.