I tried to create a new power task to power-off the system immediately, but I don't know how to fill correct "Enter credentials of the remote target" information. I tried to use OME administrator account/ remote BMC account and remote host OS account, but I got failed result as below.

The task has failed because there are no target devices or the device selected as a target does not support this type of task.
For a detailed reference on the tasks that can be run against specific devices and discovery methods,
see the Managing Remote Tasks section in the User Guide. Also check if Dell OpenManage BMC Utilities are installed.

How to resolved this issue?