wp-admin, Page Not Found.(sub-directory multisite)

What’s in your .htaccess?

This is my .htaccess:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]

# uploaded files
RewriteRule ^files/(.+) wp-includes/ms-files.php?file=$1 [L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ – [L]
RewriteRule . index.php [L]
</IfModule>

# END WordPress

# Change PHP memory limit, time limit,
# max post size, and max upload file size
php_value memory_limit 256M
php_value max_execution_time 300
php_value upload_max_filesize 32M
php_value post_max_size 32M

That’s the code for a subDOMAIN install of MultiSite (i.e. sitename.domain.com). If you’re using subfolder, try this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]

# add a trailing slash to /wp-admin
RewriteRule ^([_0-9a-zA-Z-]+/)?wp-admin$ $1wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule  ^[_0-9a-zA-Z-]+/(wp-(content|admin|includes).*) $1 [L]
RewriteRule  ^[_0-9a-zA-Z-]+/(.*\.php)$ $1 [L]
RewriteRule . index.php [L]
</IfModule>
# END WordPress

# Change PHP memory limit, time limit,
# max post size, and max upload file size
php_value memory_limit 256M
php_value max_execution_time 300
php_value upload_max_filesize 32M
php_value post_max_size 32M

Thank You! It worked!

Just in case somebody is using the Better WP Security plugin…

You can also get this problem if you turned on the “Hide Backend” feature, lost your admin cookie and are trying to go to https://mysite.com/wp-admin.

Go into your .htaccess file and you should see some lines like this:

RewriteRule ^hidden_login/?$ /wp-login.php?hyy864en85h3q03f5vfs2d [R,L]
RewriteRule ^.*wp-admin/?|^.*wp-login\.php not_found [L]

The second line shows you that wp-admin.php and wp-login.php are both redirecting to a page not found error page.
The first line shows what your alias is that you need to use to login to your site. So, the example above would mean instead of going here:

https://mysite.com/wp-login.php

I would need to type:

https://mysite.com/hidden_login

And I would be redirected to the proper site.