Jupyter kernel Apache toree startup timeout

Question

I installed toree with the following command in my Ubuntu 16.04 system:

$ pip install --pre toree

$ jupyter toree install --interpreters=Scala,PySpark,SQL 

Then I checked the kernel list. I got kernels installed succussfully:

$ jupyter kernelspec list

Available kernels:
  python3                 /home/ypdx/programs/anaconda3/lib/python3.5/site-packages/ipykernel/resources
  apache_toree_pyspark    /usr/local/share/jupyter/kernels/apache_toree_pyspark
  apache_toree_scala      /usr/local/share/jupyter/kernels/apache_toree_scala
  apache_toree_sql        /usr/local/share/jupyter/kernels/apache_toree_sql

Then I start jupyter, here comes the question: Both apache_toree_scala and apache_toree_pyspark kernel will run in error "timeout" when I create a new notebook using that kernel. Here is the error message:

Timeout waiting for kernel_info reply from d98705f0-4bba-4c69-af7f-da99379219f5

My ubuntu was installed in VirtualBox. But I think this shouldn't be a problem.