No, I did not. It worked after I did so. Somehow I missed that obvious section...
I've tried apache as well as nginx on a digital ocean server running Ubuntu 16.10. Using the default configuration for SSL listed on the nodebb site, the forums load properly but the sockets are never able to connect the user.
GET https://forum.serversite.com/socket.io/?EIO=3&transport=polling&t=Lfzci_0 400 ()