Camunda cockpit (in version 7.7.0) is running within a secure environment without internet connection, i.e. neither the Camunda server nor the client can talk with the outside world.
Observation: Both the gateway and the message icons are not shown. On an identical Camunda-installation on a normal windows box with internet, the very same BPMN-process looks fine.
I tried analyzing the website e.g. with Chrome's developer tools, inspecting elements of the Camunda page, but I could not determine who the BPMN diagram rendered. Does Camunda rely on pictures from a thirdparty server?
Any help is very much appreciated!
The solution is simple: Using Chrome's version 60 solved the issue.