ADMU3028I: Conflict detected on port Likely causes: a) An instance of the server server1 is already running b) some other process is using port

This error is seen while attempting to start the WebSphere Application server. 

Reason: The port on which the application server is attempting to start might be listening.

Check the port information using the following command.

netstat -an | grep <portnumber from the error message>

 

Since the port is listening, There will be a process attached to the listening port.

Use this script to find the process id listening on the port.

Solution:

If the port is used by a process other than your server instance, Then you have to change the port number in the configuration file(serverindex.xml).

In case if the port is in occupied by your own web server instance PID, You can kill the process id and try to start the server again.

kill -9 <PID>

Serverindex.xml: 

PATH: /opt/WebSphere/profiles/dProfile/config/cells/hostnameNode01Cell/nodes/hostnameNode01 

Check for the conflicted port and change the port number accordingly.

                                                      (: Happy learning :)