add second database to drupal site

Hi I would like to join a second database to my drupal site. I am using Drupal 8.
the two data bases are on the same serveur !
they are just using different user name.

i see this module "Views Database Connector (VDC)"

I have tried to connect the second data base as it is shown on this topic

http://drupal.stackexchange.com/questions/80989/how-to-access-the-external-database-in-drupal

But it don't work

and it does not notify me an error either!

how can I do to succeed the connection of my second data base?

thant you