Had the same error. Tried suggested plugin. It found 1655 faults and fixed them. But feed still doesn’t work. Message has now changed slightly though to:
XML Parsing Error: XML or text declaration not at start of entity
Location: https://www.scamperbranding.com/feed/
Line Number 3, Column 1:<?xml version=”1.0″ encoding=”UTF-8″?>
^
Any ideas? It used to work fine but we just upgraded to latest version of WP.
