Thanks Bruno
OK, here are the system details:
PHP version: 5.6.16
MODX version: Revolution 2.3.1-pl (traditional)
Database type: mysql
Database version: 5.6.38
The Chunk I am using is as expected, and obviously works fine, but doesn't render when viewed via https. Here it is:
[[pdoResources?
&limit=`0`
&depth=`0`
&parents=`33`
&tpl=`headerproductdropdown`
&sortby=`menuindex`
&sortdir=`ASC`
]]
"headerproductdropdown" Chunk:
<li role="presentation"><a role="menuitem" tabindex="-1" href="[[~[[+id]]]]">[[+menutitle]]</a></li>
If there is anything else I should provide please let me know.