I have the same problem, I can’t see the composer area on the left side; tested with Chrome and Edge.
When I load the page, I see the elements on the area for a very short time, but then it disappers and leaves a white space.
Where do I find php logs?
Edit: I also tested it on a test installation of WordPress on my Synology NAS. There, it works. Synology NAS currently uses WordPress 4.6.1, the real webpage 4.7.2
Edit2: It seems that there is a problem with CSS? As long as the CSS is not loaded/compiled, I see the elements. When CSS is loaded, it disappears. I am using a customized version of Courage Theme.