After using Apache httpd for over 20 years, I just discovered today, by accident, that comments are not allowed on the same line as directives in the configuration files...
https://stackoverflow.com/questions/50084211/how-to-add-comment-in-apache-ht...
https://httpd.apache.org/docs/2.4/configuring.html#syntax
Not sure how I've managed to edit those config files all these years without coming across this before!
Gilbert