When I enable caching I get this error on the frontend advising to check my .htaccess configuration.
What exactly am I looking for? I have a pretty much standard .htaccess.
Also, where are cache files stored? Is it /wp-content/uploads/asp_upload directory? If yes – looks like all those files are accessible, I provided an example link in ‘Website URL:’ section.
The problem is within the plugin, the cache is not working correctly within the current release. I’m releasing a hotfix very soon (v4.9.2) to address this issue.
Until then I recommend turning it off. Sorry about the inconvenience.