New Multisite Network: redirected you too many times

Question

I have recently turned on Multisite network for a domain.

I created a network site as a sub-directory.

When I loaded that site's /wp-admin I received an error:

This page isn’t working

dev.example.com.au redirected you too many times. Try clearing your cookies. ERR_TOO_MANY_REDIRECTS

I have cleared my cookies for this domain but the issue remains.

I have renamed plugins to plugins.temp and the issue remains.

I added the following to wp-config.php but the issue remains:

define('ADMIN_COOKIE_PATH', '/');
define('COOKIE_DOMAIN', '');
define('COOKIEPATH', '');
define('SITECOOKIEPATH', '');

This is my .htaccess:

# BEGIN litespeed noabort
<IfModule rewrite_module>
        RewriteEngine On
        RewriteRule .* - [E=noabort:1]
</IfModule>
# END litespeed noabort

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

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

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

Help appreciated.

Answer 1

I followed the advice in this answer, and changed the given .htaccess template by WP Network installation:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [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).*) featured/$2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ featured/$2 [L]
RewriteRule . index.php [L]

To this:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [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).*) $2 [L]
RewriteRule ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

Works now.