google map with all events is not shown

Hello, I want to show all event locations on a map. Unfortunately it does not work. No matter on which position I show the module. Instead of the map I get only the text (see image). I have no idea what is wrong. A map is visible in the description of each event and the individual place correctly tagged.
Using Joomla 3.4.5, EB 2.1.0, template with Gantry 4.1.29