rss feed at top of page shows error

I have tried to fix or cde the rss feed for one of my wordpress sites. I went and validated feed but don’t know where code goes in heading template? I think I’m close then nothing. The theme already had a rss feed tab at top next to facebook and twitter. my site https://www.onlinedoctorinfo.com

The rss feed I copied

<a href="https://feedvalidator.org/check.cgi?url=http%3A//ameridochealthcom.ipage.com/onlinedoctorblog/feed/"><img src="valid-rss-rogers.png" alt="[Valid RSS]" title="Validate my RSS feed" /></a>

If someone has a clue – about forever working on this and would like t start marketing instead of messing up blog completely. Thank you in advance for any assistance.