autotutorial

sorry I have no experience on old installations the public_html folder is the root in your case. is the site in this path? ^ ([0-9a-zA-Z_-]+/)?site5/files/ Optionally any letter, number, _, – and slash followed site5/files/?
delete your previous htaccess if site5 exists creates a htaccess in the site5 folder.

RewriteEngine On
RewriteBase /site5/
RewriteRule ^([_0-9a-zA-Z-]+/)?site5/files/(.+) wp-content/blogs.dir/5/files/$2 [L]

otherwise for testing insert in your htaccess root (public_html) immediately after RewriteBase /
RewriteRule ^([_0-9a-zA-Z-]+/)?site5/files/(.+) wp-content/blogs.dir/5/files/$2 [L]

Create test.php

<?php
$mysqli = new mysqli("127.0.0.1", "hashim", "password", "hashim_wordpress", 3306);
if ($mysqli->connect_errno) {
    echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
}

echo $mysqli->host_info . "\n";
$mysqli->close();
?>

http://yourdomain.com/test.php
Your default port is 3306?
Now delete test.php

For WordPress 5.2 php 5.6.20 or higther.
can you report the error in full?

Create test.php

<?php
$conn_id = ftp_ssl_connect('your domain.com',21);
$login_result = ftp_login($conn_id, "yourusername", " yourpassword");
if (! $login_result){
die("can't login");
}
echo ftp_pwd($conn_id);
ftp_close($conn_id);
?>

change your port 21 for your secure ftp, your domain without start http and end slash, rename yuorusername, yourpassword.
Delete test.php
if it does not work, check that the certificate is valid.

If, unfortunately, you still encounter problems you can choose to change method using constants in the file wp-config.php https://codex.wordpress.org/Editing_wp-config.php#WordPress_Upgrade_Constants

Before backup all file and database

https://shellcreeper.com/how-to-create-valid-ssl-in-localhost-for-xampp/ this is a guide to create a valid certificate on localhost and then choose a domain … I can’t guarantee that the bat file is free from viruses, malware or whatever.

This for multisite https://wordpress.org/support/topic/help-with-multisite-4/#post-11522419
before making changes, can you confirm if the ftps safe connection works? https://github.com/WordPress/WordPress/blob/5.1-branch/wp-admin/includes/class-wp-filesystem-ftpext.php#L64

Yes 🙂
then it depends if you have to work with a huge amount of data you have to choose the seconds that are most suitable for you .. sometimes some plugins indicate to set to 180 seconds.

to my knowledge there is no login for wordpress.org instead with wordpress.com via the jetpack login form yes.
currently the source of the login page is the default. (without wordpress.org or wordpress.com).
https://codex.wordpress.org/Editing_wp-config.php#Custom_User_and_Usermeta_Tables
Can you check in the usermeta table who is the administrator?
prefix1_capabilities = a:1:{s:13:"administrator";b:1;} and prefix2_capabilities = a:1:{s:13:"administrator";b:1;}
etc.