RSS feed for password-protected blog?

I have set up a stand-alone WP.org blog for clients only. I have password-protected the directory via the .htaccess file (Hostgator cpanel). I need to be able to send my clients my blog updates via a MailChimp (RSS campaign) newsletter, but cannot get the feed to validate.

MailChimp advises: “If you have a password protected blog or RSS feed, use the following format for your RSS feed URL: https://user:[email protected]/feed/” However, this is not working.

I tried validating it via https://validator.w3.org/feed/, using both a regular feed URL (https://dolcedesign.com/scoop/feed) and the MailChimp format (substituting the correct login/pass) but each time I get “Server returned HTTP Error 401: Authorization Required”

To create an RSS feed, all I do is add “feed” to the end of the blog URL, yes? Or do I need to do another step? This seems too easy to be true… I’ve used feedburner in the past, but not sure I need this with WP? I am using TwentyTwelve with a child theme, so assume that the RSS feed is already included..?

My understanding is that you can direct the .htaccess file to allow the RSS feed access (though I’m unclear as to what exactly you type into the .htaccess file to achieve this). When I asked my webhost techsupport (Hostgator), I was told it’s not possible to get an RSS feed to validate for a password-protected site. I have a hard time believing this, as there are many password-protected blogs out there, and I’m guessing many send out email newsletters.

Basically, it’s a private blog for clients only, and I’d like to be able to automate my newsletter using the blog’s RSS feed, without having to make the blog public. I would use the same user/pass for all recipients, and change it as needed.

I would use a plugin, but Feed Key has not been updated in 2 years. My site is a stand-alone blog, not a multi-site, so Private Feed Keys will not work (I don’t think?).