If you can not access your website, but do not have redirect loop errors, your current SSL certificate might be invalid. If you do see a redirect loop error message such as ERR_TOO_MANY_REDIRECTS, please check the Knowledge Base category “redirect loops” instead.
Really Simple SSL checks if SSL is available, and will only proceed if the test is successful. However, if you force activated SSL anyway or blocked access to the plugin folder in an unexpected way, you might accidentally have forced your site to work over SSL, which results in browsers blocking access to your site.
But if your SSL certificate is invalid, you might instead get one of the following messages:
Chrome:
ERR_CONNECTION_REFUSED
ERR_CERT_AUTHORITY_INVALID
Firefox:
Cannot connect: Could not connect to server
Safari:
Safari Can’t Connect to the Server
In such cases, you probably do not have a valid certificate. First, uninstall the Really Simple SSL plugin by following these instructions.
The next step would be to contact your hosting company and verify that the SSL certificate they installed is valid.