Get a Full Error Page When Vaidating My Feed

Hello:

I got the Feedburner Replacement plugin for my WordPress website. When I tried to validate my need I received a page ful of errors and warnings. I have no idea how to fix all this code and bugs. Here is the URL to the error page:

https://validator.w3.org/nu/?doc=http%3A%2F%2Falllivesaresacred.com%2Ffeed%2Fsubscription%2F

Here is the URL to my site: http://alllivesaresacred.com

Thank You,

Lisa DeSherlia