MetroCluster IP Mediator configuration fails with warning"Target already exists" on Mediator log

• MetroCluster IP Mediator configuration fails with the following error: 

::*> metrocluster configuration-settings mediator add -mediator-address XX.XX.XX.XX
Adding the mediator and enabling Automatic Unplanned Switchover. It may take a few minutes to complete.
Please enter the username for the mediator:mediatoradmin
Please enter the password for the mediator:
Confirm the mediator password:
Creating mediator mailboxes...

Error: command failed: The request to reach the mediator failed during the add operation.
       Check if the mediator is reachable and then try the operation again.

• Mediator log in the host machine shows the following errors:

[ERROR] [8] [restapi.py:105] ontap_mediator.controllers.targets.post_target() failed with an exception: 

  RAN: /usr/bin/sudo scstadmin -noprompt -add_target iqn.2012-05.local:mailbox.target.xxxxxxxx-f528-11eb-9a45-d039ea3015f7:xxxxxxxx-f51f-11eb-aa3c-xxxxxxxx:1 -driver iscsi -attributes 'MaxSessions=4,IncomingUser=mccadmin xxxxxxxxxxxxxxxx'

  STDOUT:

Collecting current configuration: done.

-> Making requested changes.
    -> Creating target 'iqn.2012-05.local:mailbox.target.xxxxxxxx-f528-11eb-9a45-d039ea3015f7:xxxxxxxx-f51f-11eb-aa3c-xxxxxxxx:1' for driver 'iscsi': done.
    -> Done.

WARNING: Received the following error:

    Target already exists.