Solr Exception: Sort param field can't be found
<p>I've been trying to set up CKAN, however I am facing some problems in SOLR.
Everytime I run CKAN, the SOLR log file registers a new event, and that is:</p>

<pre><code>org.apache.solr.common.SolrException: sort param field can't be found: metadata_modified
</code></pre>

<p>I am trying to use CKAN for the first time and I have no experience at all, so I have no idea what that log event means, nor how to fix it.</p>

<p>EDIT:
When I reload the core at SOLR, the following is logged:</p>

<pre><code>The schema has been upgraded to managed,&amp;#8203; but the non-managed schema schema.xml is still loadable. PLEASE REMOVE THIS FILE.
</code></pre>

<p>Could anyone help me?</p>

<p>Many thanks.</p>