Hi Craig,
I was about to post a thread raising the same issue that @dickkirkland has posted about, but I thought I’d just post here instead.
I’m having the same issue with a site. I’ve enabled “Cache Error API Recheck”, enabled “Backup Caching”, cleared the Backup Cache and set “Force cache to clear on interval” to Yes.
I spoke to our hosting company and they tested the caching by uncaching it. That did not fix it though, so they said it’s not a caching issue. There was also nothing in the error logs for the plugin, though they said it didn’t look like any had been implemented other than a splash warning.
Do you have any idea how I can get rid of this message and fix the problem?