I wasn’t able to connect to an iDRAC on a Dell PowerEdge R710. It was plugged into an active switchport but just would not get link. With OpenManage Server Administrator installed on the server I looked at the Configuration tab in the Remote Access section.
I noticed that NIC Selection was set to Shared. That seemed odd so I compared that setting to another R710. The other one was set to Dedicated. I switched the problem one from Shared to Dedicated & it started working.