I did in fact turn debug to =1
Anyway did it again - went through all my pages and found errors on my rss feed, feed was empty - as I have not made a new post for a while - adding a new post removed the error and feed was working, deleted new entry and feed broke.
I have another rss feed that was ok so I used that code instead and seems to have cleared error (even with new entry deleted)
old rss code below - maybe there was something wrong in it…
{exp:rss:feed channel="mychannel"}
<?xml version="1.0" encoding="{encoding}"?>
<rss version="2.0"
xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
xmlns:admin="http://webns.net/mvcb/"
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:content="http://purl.org/rss/1.0/modules/content/">
<channel>
<title>{exp:xml_encode}{channel_name}{/exp:xml_encode}</title>
<link>{channel_url}</link>
<description>{channel_description}</description>
<dc:language>{channel_language}</dc:language>
<dc:creator>{email}</dc:creator>
<dc:rights>Copyright {gmt_date format="%Y"}</dc:rights>
<dc:date>{gmt_date format="%Y-%m-%dT%H:%i:%s%Q"}</dc:date>
<admin:generatorAgent rdf:resource="http://expressionengine.com/" >
{exp:channel:entries channel="mychannel" limit="10" dynamic_start="on" disable="member_data"}
<item>
<title>{exp:xml_encode}{title}{/exp:xml_encode}</title>
<link>{comment_url_title_auto_path}</link>
<guid>{comment_url_title_auto_path}#When:{gmt_entry_date format="%H:%i:%sZ"}</guid>
<description><![CDATA[{article_para_one} <a href="http://{title_permalink=">Read More & Comment</a>]]></description>
<dc:subject>{exp:xml_encode}{categories backspace="1"}{category_name}, {/categories}{/exp:xml_encode}</dc:subject>
<dc:date>{gmt_entry_date format="%Y-%m-%dT%H:%i:%s%Q"}</dc:date>
</item>
{/exp:channel:entries}
</channel>
</rss>
{/exp:rss:feed}