RSS feed missing style information

hope someone can help me, i think this is something simple… but my brain is overloaded from troubleshooting all day on a hacked account.
when you click my feed button, it redirects to a page with this at the top “This XML file does not appear to have any style information associated with it.” so everything just appears below as code.
i just had to downgrade to 3.0 after trying to upgrade, in response to the hack, and discovering that my hosting php version was incompatible. i’ve fixed everything else broken, but again i think my brain is just tired. can anyone direct me to the fix? would much appreciate it. thanks!