When access a protected directory, login/password is not asked, only error is shown:
403 Directory index forbidden
Also, this error may occur if you access not protected but the regular directory.
Directory index forbidden error occurs if there is no index file in the directory and directory indexing is disabled in Apache configuration.
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
Or enable directory indexing with
Options +Indexes directive for the domain by means of
vhost.conf or for the whole server in
Restart Apache if you changed any configuration file.