Problem with RSS after installing Sucuri

The rss feed to campaign stopped parsing the feed after installling Sucuri and after contacting Mailchimp support they indicated me that the current feed is no longer valid according to this:

https://validator.w3.org/feed/check.cgi?url=otzerling.com%2Ffeed%2Ffeedname

Is important because through the rss, events are sent automatically to the subscribed mailing list. The error is: connecting to feed failed.