You have attempted to modify a SCSI host port with a conflicting port ID and the same worldwide port name (WWPN) as an already existing host port. You cannot enable the same port ID on SCSI host ports that have identical WWPNs.
Ensure that you enable a different port on the SCSI host port with the same WWPN and resubmit the task. If the problem persists, contact IBM technical support for assistance.