getting 404 error

Hi WP Fastest Cache,
I’m getting a 404 error when trying to clear all cache. Needed to clear site cache so went to “delete cache” tab like normal and clicked “delete cache” button and I keep getting a 404 page not found error. Plugin is v0.8.8.6.

I tried a few things but didn’t work. So I deactivated and deleted the plugin. I made sure all .htaccess info was removed when I deleted the plugin. I then downloaded it again / activated but when I go to the settings tab to “enable” and save – it goes to the 404 page again. It will not save and getting the same result as before.

Any thoughts – thanks in advance!