Sitemap.xml not showing

<%- if @topic_view.topic.tags.present? %>
<%= t 'js.tagging.tags' %>: <%- @topic_view.topic.tags.each do |t| %> <%= t %> <%- end %>
<% end %>

Google sitemaps module (

I installed Google sitemaps module using composer, added the suggested googlesitemaps.yml file and copied and pasted suggested config (removing the tabs with spaces), did a dev/build and went into one page to choose a specific Page Priority.
When I try to access the mylocaldomain/sitemap.xml shows an empty white page and on it seems I am in a loop (page reloads forever, but website has only 5 pages - all on first level nav). That’s what happens in Firefox browser.
In Chrome I get the following url:

Is there anything else I have to configure?