Possible Htaccess file issue – MU site not working

Hi all,

I’ve set up a couple WordPress multisites in my time so I know how to do it. This time I’m setting up a multisite at another hosting and it’s not working for some reason.

I’ve already been in touch with my hoster and the do support wildcard domains. I checked with them and we made sure they are set up correctly.

Here’s the situation:
My main domain is InMaastricht.com. I’ve enabled the multisite network setup there and completed it. I can access the Network Admin section.
I’ve added the right rules to the Wp-config file and to .htaccess.

When I create a subdomain now and try to visit it I see the regular Apache page. An example can be seen at test.inmaastricht.com. When I try to visit test.inmaastricht.com/wp-admin I get a 500 Internal Server error.

The hosting company said it’s probably the rewrite rules on my .htaccess file. Unfortunately I don’t have enough knowledge on how to do fix the file to make sure it works. Here’s what currently in my .htaccess file:

# BEGIN WordPress
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]
# END WordPress

I have no clue what to do next. I really need the site to work and I hope someone here can help me fix it.

Thanks in advance for your time and expertise.

Michiel