Setting up RTMP server settings

I’m setting it up for the first time.
I’m in add new RTMP server.
I think the NAME I use doesn’t matter.

BInding address I chose “any interface” since I don’t know what else to use.

PORT had 1935 so I left it as it was.

I have a stream key so I am using it.

The “ADD” button is not active so I can’t click it.

What did I miss?