toni-english.com My latest issue has been that the CSS, and therefore theme, did not render. I got just a list of links and content. Nightmare. My site appeared fine on my desktop. But when I went to the site on other desktops, I also think depending on browser, it was the mess. And always a problem on mobile.
I deactivated all plugins. Sigh, I hate that so much. And saving a lot more detail, I figured out the plugins causing problems. It has not been 100% solved, but this is my conclusion thus far and why:
The problem was with a great plugin called RS Head Cleaner Lite. Problem created by JetPack.
I have used this plugin RS Head Cleaner Lite, and still do, on several sites – without issue. Even in a subsite of the same MultiSite install of the site with the problem – toni-english.com/quiz. It speeds up the loading of my sites big time. I use a lot of plugins. It is the only plugin of this type that I trust. Even now it has done no damage. And I have had damage my friends from others.
The one thing that I did differently on this site, that I have never done before, was that I had activated JetPack mobile view. Where JP renders your site for mobile devices. Now, though JP mobile view is deactivated I still cannot use RS HCLite. JetPack has changed something. I call that Damage.
Note: The developer of RS Head Cleaner Lite is working on this. He was immediately responsive on the support forum and has kept in close contact with me via email.