404 going to default page as standard

[PeterK]

My 404 pages don't seem to be working correctly. Instead of the custom 404, the server just return the index page of the site. This is causing problems with search engine spidering.

I have a 404.shtml in the root directory and looking in the .htaccess I see nothing to make this redirect happen.

The site is a Addon Domain.

Any ideas?

[PeterK]

Ok, I fixed it.

The main root .htaccess had a rewrite rule that was inherited by my addon domains .htaccess file.
I just added a RewriteEngine Off to the addon domain's .htaccess file and now is all good.