Mobile version showing on desktop

The mobile version of my site is showing up on desktops. I’ve tested it on different browsers and computers: Safari, Chrome, Edge, Mac, PC. It is not consistent as to which browser it decides to use it.
Everything I have researched suggests it’s a caching issue.I have turned off my caching plug-in (W-3 Total Cache) with no results. Turned it back on and reconfigured it several different ways after researching W3 website and WordPress Forums. Still no change. I have emptied my browser cache as well. It just started happening today as far as I know.
This is my site: kikicuppycakes.com