500 Internal Server Error (2 weeks)

Hello,
About many days or 2 weeks can i not lost this problem.
I have search on the forum, youtube, google but nothing work.
I will to install wordpress on my website. My web hosting is cpanel.
If i download the 3.3.1 zip file from wordpress site then i go to wp-config-sample.php then i fill in:

// ** MySQL settings - You can get this info from your web host ** //
/** The name of the database for WordPress */
define('DB_NAME', 'databse name HERE');

/** MySQL database username */
define('DB_USER', 'database user HERE');

/** MySQL database password */
define('DB_PASSWORD', 'database password');

/** MySQL hostname */
define('DB_HOST', '<strong>i tried localhost, www.mywebsite.com, https://mywebsite.com, https://www.mywebsite.com</strong>');

Then i upload all the files in Public_HTML
So, normal it must now working if i go to https://www.mywebsite.com/wp-admin.php or /wp-admin/install.php
Then i go to softaculous and install wordpress. I tried https://, https://www, and with (S).
I clear the wp text directory.
Database name: kouwro_athome
Table Prefix: wp_
I tried to enable the: Enable Multisite (WPMU)
Admin Password: same like database password.
Then i click install. If its ready then i got 2 links (mywebsite.com and wp-admin.php)
If i click on the link (my website) then i got this message:

Internal Server Error

The server encountered an internal error or misconfiguration and was unable to complete your request.

Please contact the server administrator, [email protected] and inform them of the time the error occurred, and anything you might have done that may have caused the error.

More information about this error may be available in the server error log.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

This is the errors in the log file: (cpanel)

https://pastebin.com/LrEHNKc4

Please help my with this.
I hope this is enough information.

King Regards, PcWolf