The page isn't redirecting properly

https://ece.scisdragons.net/amiller

On one of my sites in a multisite config, others work fine, I’m getting:

The page isn't redirecting properly

          Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

  This problem can sometimes be caused by disabling or refusing to accept
    cookies.

I have already tried to clear cookies etc.

My .htaccess file is:

# BEGIN WordPress
AddType x-mapp-php5 .php
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).*) $2 [L]
RewriteRule  ^([_0-9a-zA-Z-]+/)?(.*\.php)$ $2 [L]
RewriteRule . index.php [L]

<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

# END WordPress