Balsamiq not working in Confluence Cloud (OnDemand)

Cause
javax.servlet.ServletException: Servlet execution threw an exception
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:313)
caused by: java.lang.NoSuchMethodError: com.atlassian.confluence.admin.actions.ViewOrUpdateLicenseAction.getLicense()Lcom/atlassian/license/License;
    at com.balsamiq.confluence.plugins.mockups.MockupsLicenseManager.getConfluenceUsers(MockupsLicenseManager.java:399)