Container with external database very slowly

Good evening,
I have a problem with Docker on Windows.
I have a container with Drupal CMS. Drupal uses a MySQL external database located on a VM.
When the CMS tries to write or read from the external database it takes a long time, on average two minutes.
If I move the local database to the container instead everything runs smoothly.
Do you have ideas on the reason for this slowness?

What version of Docker for Windows are you using? The latest beta have improved networking performance.

If you upgrade and still find performance to be slow, please open an issue with more details here: https://github.com/docker/for-win/issues/new

Thank you for your reply.
I’ve upgrade engine and now not have problem.