Bamboo Spec implementation uses Apache HttpClient to connect Bamboo server. Apache HttpClient ignores the system proxy setting by default. The well known system properties don't work:

System.setProperty("http.proxyHost", "proxy.server.com");
System.setProperty("http.proxyPort", "1234");

Could you please extend the implementation of the class

com.atlassian.bamboo.specs.util.RestHelper

The Apache HttpClient instance created by RestHelper must be aware of the system properties. It looks similar to this:

HttpClientBuilder.create().useSystemProperties().build();