The out-of-the-box default-config is setup to automatically select
different ports when an instance runs on the same host as the DAS. No
modification of the config is necessary.
You can turn on javax.enterprise.system.tools logger to get more
information.
When starting the remote instance, the DAS uses a SSH command to run
start-local-instance on the remote host. So it doesn't actually have to
connect to the server that is started using HTTP. It appears that the
HTTP connection is where the problem is.
Tom