 <p>I found the problem, I had specified the index <code>my_index</code> in the server box on sense. Removing this and re-executing the post command as:</p> <pre><code>POST /my_index/_search?scroll=10m&amp;search_type=scan { "query": { "match_all": {}} } </code></pre> <p>and passing the resulting scroll_id as:</p> <pre><code>GET _search/scroll?scroll=1m&amp;scroll_id="c2Nhbjs1OzE4ODY6N[...]c5NTU0NTs=" </code></pre> <p>worked!</p>