Don't see "Ignored Query Strings" specifically. When I click the "here" link, I do see "Ignored Query Stems" section. I add the "_wp_session_" and click save changes, but the error still remains. What gives?
"In order for database caching to work with WooCommerce you must add _wc_session_ to the "Ignored Query Strings" option in W3 Total Cache settings here."