Wordpress HTTP Request 501 Internal Server Error - wordpress

Question

Hello i have digitalocean one click application contains Wordpress.
I add domain to my server and create SSL certificate for my server.
https://example.com works good but when i request
http://example.com its redirect -> http://myserverip.com and gives that error:
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request.
Please contact the server administrator at webmaster#localhost to inform them of the time this error occurred, and the actions you performed just before this error.
More information about this error may be available in the server error log.
Additionally, a 301 Moved Permanently error was encountered while trying to use an ErrorDocument to handle the request.
Please help me about it. I try to redirect http to https but its not work!
Here it is my .htaccess file contains:
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^(.*)$ https://%{HTTP_HOST}%{REQUEST_URI} [L,R=301,NE]
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

Answer 1

Try this, worked for me:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
RewriteCond %{HTTPS} =off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [QSA,L,R=301]
</IfModule>