I can fix the settings of the 2nd player..
but I can't fix my own settings

you know that I mean?D:

No, i dont know what you mean.

Please explain, i would like to help.

hmmm

Example:
I want to play parkour
the first in the line its me
the 2nd in the line is coloo

I'm a bit high of the floor BUT, I can't fix it
coloo is a bit high of the floor and yes, I can fix it

and thanks.

Ahh that, what you do is just kill the server, and start a new one, it is a common bug i have had problems with, you just start a new server.

I did...about 3times.
I'll keep trying
thanks

Use this command.
/set engageplayerpos 0
No need to change server :|