This can be caused by your server configuration, or by the SSL certificate. Read this article on how to check if it is caused by your certificate. For the server configuration, you can try the steps below.
On some servers, Safari may have issues with certain .htaccess redirects. To solve this, you can either remove the .htaccess redirect by
- Activating “stop editing the htaccess” in the Really Simple SSL settings
- Deleting the Really Simple SSL comments from the .htaccess
Or you can try different .htaccess rules. I’ve had reports that the following did work in one such case
RewriteCond %{SERVER_PORT} !^443$ RewriteRule ^(.*)?$ https://%{SERVER_NAME}%/$1 [R=301,L]
Though this is certainly not a best practice, and will not work always.
If you have this issue, please let me know if you found another solution or if this did work for you.