No SSL Detected

Hello Really Simple SSL,

when I activate Really Simple SSL I get this error:
No SSL was detected. If you do have an ssl certificate, try to change your current url in the browser address bar to https.

If I change my url to https my Chrome Browser is telling me that My connection is not private
and in the address bar a red and crossed out lock and https appears.

If I am running the reall-simple-ssl/ssl-test-page.php with http in front of it i get this
error #NO KNOWN SSL CONFIGURATION DETECTED#

doing the same step with https in front of it will give me the error as above
My connection is not private…

cant find anything about it in the internet and even a similar article was not helping
somehow my problem must be different even though my hosting provider assures that ssl is active

https://wordpress.org/plugins/really-simple-ssl/