I had the same issue but only with Chrome. I disabled the “Chrome Data Saver” extension and the error went away.
Turns out that my hosting provider had a cache of their own. I cleared that and everything worked.
Turns out that my hosting provider has a cache of their own. I cleared that and my changes started to make effect.
I did too but then I removed the plugin and re-did everything. I followed a tutorial
https://bloggingwizard.com/w3-total-cache-cloudflare/
to set it up and now it works fine.
