Scoreboard teams problems

Hello, my friend when he joins the server he gets the team, but after sometime the team keeps changing. Any fixes?

Quote from Minetopia135796NL

what do you mean by teams

use you a plugin?

bartekmikosz

I am using minecraft's default command /scoreboard teams

Quote from WicHenery

Have you ever known about /scoreboard command before?

Yes i am using this command, still have issues