SYMPTOMS
When I access the protected directory, I am not asked about the login/password, but get the 403 "Directory index forbidden" error instead. Also, this error may occur if you access not protected but the regular directory.CAUSE
"Directory index forbidden" error occurs if there is no index file in the directory and directory indexing is disabled in Apache configuration. See http://httpd.apache.org/docs/2.0/mod/mod_dir.html#directoryindex and http://httpd.apache.org/docs/2.0/mod/core.html#options for more information.RESOLUTION
To avoid this error the index file should be put into the directory. Index file's extensions are defined in httpd.conf by means of DirectoryIndex directive, for example:
DirectoryIndex at_domains_index.html index.html index.html.var index.shtml index.php index.htm
see http://httpd.apache.org/docs/2.0/mod/mod_dir.html#directoryindex for the detailed description.
Or enable directory indexing with "Options +Indexes" directive for the domain by means of vhost.conf or for the whole server in httpd.conf, see http://httpd.apache.org/docs/2.0/mod/core.html#options for the directive syntax.
Restart Apache if you changed any configuration file.