<Doesnt't work(displayed) RecyclerView of List of ...

# stackoverflow

[user]

Doesnt't work(displayed) RecyclerView of List of users (android, Kotlin, RecyclerView)
When the Application is launched after user authentification, nothing is displayed when switching to activity_main ( EXCEPT for one line of the separator of user Field name, you can scroll the activity itself)
The sourse code seems to be correct ;).

My MainAcivity class:

class MainActivity : AppCompatActivity() {

private lateinit var userRecyclerView: RecyclerView
private lateinit var userList: ArrayList
private lateinit var userAdapter: UserAdapter
private lateinit var mAuth:...