According to the Lotus Connection Information Center (
http://publib.boulder.ibm.com/infocenter/ltscnnct/v2r0/topic/com.ibm.lotus.connections.help/r_api_comm_get_service_doc.html) to retrieve the service document for communities you append "/service/atom/service" this to URL.
But this is not working
My URL is
https://***********.***.***:9443/communities/service/atom/service
Any help would be appreciated.