Blog Feed Messed Up

I am using the newest version of WordPress with the iNove theme.

My blog, Osneo.com, is having weird problems with it’s feed. If you go directly to Osneo.com/feed, it redirects perfectly to the feedburner page (https://feeds.feedburner.com/osneo) I made for it. I’m using a plugin to make it do that.

However, if you click on one of the buttons in the RSS button on the top of the sidebar, it redirects to https://www.feeds.feedburner.com/osneo. I don’t know why, but if you put that “www.” with the “https://” in the feedburner address, it doesn’t work! (It says the page doesn’t exist…) And the main way anybody’s going to subscribe to my blog is through the sidebar button.

If all the feeds are changed to redirect to the feedburner page (https://feeds.feedburner.com/osneo), then why is the RSS button in the sidebar adding that “www?”

Most importantly, how can I change it so there is no “www,” only “https://?”

Thanks for your help!