Sending Blog Posts to List Subscribers

Can any body help me with this problem? I've been asking for help everywhere and nobody has an answer. So, I figured somebody here has had to run into this problem at one time or another. Here goes:

I have a client who wants her wordpress blog posts to automatically be sent to her newsletter subscribers. I figured this should be pretty easy because I could just set up her campaign profile on her autoresponder service to send rss to email. Well, I set it up and her subscribers get the message that she has a new post on her blog, but when they click on the link, they get an error message that the page cannot be found.

First off, I had to set up her wordpress blog as a sub-domain of her website domain. She didn't want a separate domain for her blog. I think the problem has something to do with the fact that she set up her main website as a website tonight on godaddy a few years ago and paid up to 2015 for it. So, when I set up her wordpress blog and entered the rss url as http://sub-domain.domain/postname -- the autoresponder is looking for a directory on her domain rather than the postname. If I am correct, how do i fix this?

If I am not correct in my thinking, does anybody know what the problem is and how do I fix it?

Any help on this would be greatly appreciated!!