An action task for Set CPU Count or Set Memory for VM has a Failed status in the recent task list because power off is not allowed.

The Recent Tasks list indicates that a Set CPU Count, Set Memory, or Set CPU and Memory task has a status of Failed. When you evaluate the Messages list for the selected task, you see this message.

Unable to perform action. Virtual Machine found
	 powered on, power off not allowed 

When you increase memory or CPU count, you see this message.

Virtual Machine found powered on, power off not allowed, if hot add is
	 enabled the hotPlugLimit is exceeded

You submitted the action to increase or decrease the CPU or memory value without selecting the Allow Power Off option. When you ran the action where a target object is currently powered on and where Memory Hot Plug is not enabled for the target object in vCenter Server, the action fails.

1

Either enable Memory Hot Plug on your target virtual machines in vCenter Server or select Allow Power Off when you run the Set CPU Count, Set Memory, or Set CPU and Memory actions.

2

Check your hot plug limit in vCenter Server.