I'm sure it is not the answer you are looking for: don't use MacOS Sierra. It is way too new an OS for anything that just has to work. If it ain't broken, don't fix it.
I appreciate that Wim thanks. Always good advice. Sometimes we just need someone else to remind us!
Sierra aside and saying we stay on 10.11, do you have any idea if what I proposed can work with FMS 15 and Server.app? There was a lot of debate about this back a couple of years ago when we no longer had the option to use our own web server for Custom Web Publishing.
I'm just looking at options that would be easier for me to deal with than what I am running now.