@Pankaj Chaurasiya
Can you double check if you have used the correct port 2222 to login to Sandbox? (Sandbox runs inside docker container hence the SSH port is mapped to 2222)
# ssh root@127.0.0.1 -p 2222
Enter Password: hadoop
.
Or use the Http Based WebClient terminal to login to Sandbox:
http://localhost:4200
.
After using the correct SSH port you should be able to use the hadoop commands and should be able to see all the users.