Game server performance.

Already checked, it's fine

How did you check the game server?

I think i understood wrong, my mistake. What do you mean by that then?

The game server may be experiencing degraded performance issues.

But it's been going on for weeks, and my friends don't have issues

Depends on you location/region. It's possible the games connects to a sever on a different content for example. Which would increase latency a lot.

Are your friends from the same area and have the same ISP? Do you have the same ping as them when you go to their house? These things would help diagnose the problem.

We live close to eachother. The thing is that my brother lives in the same house and he does not have any problems

Then its probably a multi faceted problem between your computer, the protocol that the game uses.

Is he on console or PC?

PC

sorry