Quick Tip - Enable failed request tracing in IIS for status 200 to log Request Data and search for GENERAL_REQUEST_ENTITY in the resulting trace file.
Office web apps for SharePoint 2013 not working after security updates / server patching. After installation of the following security patches, OWA stopped working there by causing issues with SharePoint 2013. Details of ULS logs are provided below. FarmStateReplicator.exe (0x0CD8) Office Web Apps Farm State Error when trying to connect to Farm State Manager service: System.ServiceModel.EndpointNotFoundException: There was no endpoint listening at http:// /farmstatemanager/FarmStateManager.svc that could accept the message. This is often caused by an incorrect address or SOAP action. See InnerException, if present, for more details. ---> System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress) at System.Net.ServicePoint.ConnectSocketInternal