My map doesn't display

Wordpress: version 4.6.1–fr_FR
Geodirectory: 1.6.9
Themes tested with the same issue: Kleo, Smartmag

Hi team,
I’ve an annoying issue with GD: it is impossible to set up the default location. I’ve downloaded dummy data and did (I think) made everything correctly. When I click on the “set default location”, the map appears very briefly and disappears, leaving the place to a wide grey area and (translated):
“There’s a small problem – Google Maps didn’t load correctly on that page. For further technical informations about that issue, please see the Javascript Console”

Any idea of what it could be? Thanks a lot for your answer and by the way, seems to be a great plugin!

Olivier