Subdomain with htaccess not working

I've just setup a subdomain for my site.

My problem is: when I go to http://xyz.site.com I didn't see anything. Only "The link appears to be broken". But when I go to http://xyz.site.com/index.html all it works fine.

The problem is in .htaccess:

Options +FollowSymlinks
RewriteEngine on
RewriteBase /

RewriteRule ^([a-z0-9]+)/开发者_如何学Python?$ profile.php?id=$1 [NC]

If I comment the RewriteRule it works correctly.

How can I fix the htaccess? Maybe with a RewriteCond?

Thanks.

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I will set a default page in .htaccess if I were you.

DirectoryIndex index.html