If Im logged into my Microsoft account and someone on a different console tries to log in,...

Yes, that is allowed. Although, keep in mind that sharing accounts is a violation of the code of conduct, so depending on what you're trying to accomplish, you could be putting yourself at risk for being banned.

It would allow them to sign in. If they try to play a game, it will kick you off your game.

okay, what if they use an app like Netflix while im playing a game? will it allow both at the same time?

ive tried it on different devices and the same thing happens everytime but this only happens to te account im trying to log into ive made a new accout and i logged in with no problems it just happens to my main account

She was the first to log into fortnite on the xbox. When i tried to log my epic account on it from my profile, it just brings up her fortnite account even if im on my profile. We share one xbox with 2 different microsoft accounts and we share the gold
for multiplaying. The only way to log her out is to unlink it from the epic games website. I can play everything else independently, but so far have been unsuccessful on having two fortnite accounts on one xbox, even on two different accounts. I know how the
sharing works, This is Fortnite specific on ONE console.