Problem with my RSS feed – The URL does not appear to reference a valid XML file

I’ve recently sent out a new email campaign via Mailchimp telling my blog subscribers that they’ll have to opt back in if they want to continue receiving my new posts in their inbox every week.

One lovely subscriber came back to me and told me that she hasn’t been receiving my new posts in her inbox for quite some time. I’m not sure why it’s stopped working, but from my limited knowledge I’m guessing it’s a problem with my RSS feed.

I went on to Mailchimp to try and set up a new campaign to automatically sent any new posts I publish to my subscribers by email, but I’m just getting an error message when I type in my RSS url (as found in my Page Source).

I went on to Feedburner to investigate this and attached is the error message:

“The URL does not appear to reference a valid XML file. We encountered the following problem: Your feed has an invalid character(s) in it. This may be caused by editing your posts with a wordprocessing program. Try copying your posts into a plain text editor (like Notepad or TextEdit) before pasting them in your blogging tool.
Identify Feed Source
Back to My Feeds
The feed URL you entered is:
https://galloparoundtheglobe.com/feed/
We could not find a valid feed at that address. Here are some possible reasons this might have happened:
Is the feed valid? Confirm its validity now.
The feed your site already creates needs to be “valid enough” to work with FeedBurner. This post from the FeedBurner Help Center explains why technical validity matters.
Are you using the URL of the web page or the URL of the feed?
FeedBurner is usually able to “auto-discover” your feed from a web page, but in this case we didn’t find any related feeds. You may want to enter the URL of the feed directly.
Is the URL is misspelled or a copy+paste action didn’t work?
If that’s the case, please try again.”

My technical knowledge is really limited, so if anyone knows how to fix it, please tell me in very simple language and with step by step instructions. Many thanks ??

The page I need help with: [log in to see the link]