Unable to connect to JBoss EAP via CLI

Issue

• We are unable to connect to the cli using jboss-cli.sh or jboss-cli.sh -c. The CLI only starts when we use: jboss-cli.sh --connect controller=$HOSTNAME:9999

• I tried jboss-cli.sh --connect controller=localhost:9999 and received the following error:

  "Caused by: java.io.IOException: java.net.ConnectException: JBAS012144: Could not connect to remote://localhost:9999.
  

• When using jboss-cli from JBoss EAP 7 to connect to a default installation of JBoss EAP 6 the connection succeeds. However, if we change the native port in JBoss EAP 6 to any value (regardless the approach - port-offset, JVM parameter, etc.), the connection fails with the following output:

  Failed to connect to the controller: The controller is not available at localhost:10099: java.net.ConnectException: WFLYPRT0053: Could not connect to http-remoting://localhost:10099. The connection failed: WFLYPRT0053: Could not connect to http-remoting://localhost:10099. The connection failed: XNIO000812: Connection closed unexpectedly
  

  or

  Failed to connect to the controller: The controller is not available at g60mps-sso02:10090: java.net.ConnectException: WFLYPRT0053: Could not connect to remote+http://g60mps-sso02:10090. The connection failed: WFLYPRT0053: Could not connect to remote+http://g60mps-sso02:10090. The connection failed: Connection refused