Validate Feed Problems

I am a newbie.

I have been trying to validate the feed for my blog.

Here is the blog:

https://hawaiisecret.com/blog/

Here is the feed (I think):

https://hawaiisecret.com/blog/feed/

Here is the error page from feed validator:

https://feedvalidator.org/check.cgi?url=http%3A%2F%2Fhawaiisecret.com%2Fblog%2Ffeed%2F

Am I doing something wrong?
Is there something wrong with my settings?
My blog?

How do I fix this?

Please help. I am very frustrated by this.

thanks in advance