RSS Feed doesn't contain valid links

[dominicporter]

I have my WP site set up to send mailchimp emails for new posts. The URLs in the emails (or the 'view in browser pages' of the emails) don't work. Having done some digging, I used this feed validator on my site:

https://validator.w3.org/feed/check.cgi?url=http%3A%2F%2Fsmallworldadventures.net%2Ffeed%2F

and right at the top I see:

line 13, column 8: link must be a full and valid URL: / [help]

	<link>/</link>
        ^

This may just be a config thing I have wrong... if so maybe someone can tell me how to fix it... but it looks like the domain is not being set correctly in the RSS feed.

PS this is a self hosted sandcats domain with a custom domain for the WP grain.