Since FileMaker Server version 13, FMS has used its own Apache configuration files on macOS instead of just adding includes to the OS configuration files. Because of this, the technique I mentioned here no longer works for newer systems. This new arrangement has reduced issues for FileMaker Server’s web connectivity.
Besides being a bit of a mouthful, debugging Apache configuration issues has gotten slightly more complicated after Apple released the Server 2.2 update for Mac OS X Server.
Formerly, you could do a basic configuration check this way: