RSS into a newsletter, am I just outdated?

`Hi All,

Just wondered if anyone could assist with this,. Last year I managed to do RSS feed newsletters through mailchip at the time which worked awesome. The only issue that I'm gettin is that I've tried every tried to put this feed - into an rss generator and it keeps coming up with an errror that the page is a website and not a direct feed file.

Am I just outdated or is there a new way to make it easy to email selective categories based on a subscription to the user?