For a few days it has been in mc for me and i'm kicked by the server. Can wr help?
I'm afraid
Someone could have hacked your account, the best thing to do is to change your password immediately.
You can change it here: https://www.minecraft.net/...e-de/login
Change your password, and your e-mail password, and the password from the backup e-mail from your e-mail (if you have one). Your account has likely been stolen.
Will they be logged out?
Yes!
Before you worry too much, check whether you accidentally opened Minecraft twice. It often happens that you do not log out correctly and this message appears when you log in again.
This also happens with many of my players and their accounts were 100% not hacked or misused. It's just an accident.
Close Mincraft completely (not with the cross), but end the game correctly, restart it and log in.
Shouldn't happen again then.
This could be a server issue, I am on a server and got disconnected cause it thought i was on the server when my game crashed and i rejoined.