Failure of server APACHE bridge:
No backend server available for connection: timed out after 10 seconds or idempotent set to OFF or method not idempotent.
If there is an issue with the oacore managed server, meaning apache is not able to connect to the oacore managed server, you'll see this error.
It is possible that the managed server oacore is not yet started, and you try to access the EBS URL.
It is possible that the managed server for oacore is not able to start up because of a port conflict.