it is spawning me at Y negative 2000

What I expected to happen was...:
join my friend's server and spawn on the surface

What actually happened was...:
when i join my friend's server it spawn me at Y negative 2000 until i drop to Y negative 4000 it kick me out. And i can do nothing about it.  

Steps to Reproduce:
1. joining my friend's server
2. show up my character 
3. press f3 and see that my coordinate of Y become -2000