Not able to setup connection between Intune and Defender

Question

I have followed the steps mentioned in the highlighted portion of the screenshot, but not able to setup the connection. Connection status show Unavailable only.

Can someone please help me debug the issue here and what needs to be done to fix this.

Also what are the pre-requisites if any for the connection to be established.

Also if this is supported in only enterprise plans, please suggest me the minimum required license/plan for the connection to be established

Thanks