Robots.txt is not being generated

We’re setting up a new WP site on our server. Using v.4.3.1 and all plugins are up-to-date.

I was configuring Google XML Sitemaps where it offers to add the sitemap to the virtual robots.txt.

I do some research, removed the hard-copy robots.txt I had placed there when first setting up the account. Then I try http://mydomain.com/robots.txt – and I get a “not found.”

Do some more research. One source says there’s no vitrual robots.txt until there’s a post. So I post a test post. Nothing.

Some sources say I need to set Settings > Reading > Search engine visibility. I make sure that’s unchecked. Still nothing.

I check from another box just in case my cache is preventing view of the the virtual file. Nothing.

So I install Multipart robots.txt editor plugin just to see if that will do anything. It has a robots.txt preview button. Still nothing.

On the site, ownership is all www-data. Perms are usually 755 for directories and 644 for files.

So where the heck is this vitrual robots.txt file? Why won’t it generate? Help!!!