I am trying to add an existing MySQL database as a source database to a docker container running Apache Superset. The MySQL database that I am trying to add is not running in a docker container. It's an existing MySQL database running on a Windows machine.

I've added `mysqlclient==1.4.6` to `requirements.txt`. The error message seems to indicate that the driver is installed.

I've used `mysql://user:password@127.0.0.1:3306/database_name` and `mysql://user:password@localhost:3306/database_name`

The error I get is:

> 
> "ERROR: Connection failed, please check your connection settings."
> 
> 
> 

I am using image: `apache / 'incubator-superset' v. 0.36.0`

Are there any settings or config that needs to be changed to be able to communicate to an external database from within a running docker container?