ActionView::Template::Error (No route matches {:action=>"show", :controller=>"spree/admin/themes_preview", :theme_id=>nil}

[matissg]

Hi,
First of all it's great, you've created themes for Spree and I'd love to try some of them out.
At the moment I'm a bit stuck as I get this error:

Showing /mnt/c/sites/myappname/app/views/spree/layouts/spree_application.html.erb where line #21 raised:

No route matches {:action=>"show", :controller=>"spree/admin/themes_preview", :theme_id=>nil}, possible unmatched constraints: [:theme_id]

<%= render partial: 'spree/shared/sidebar' if content_for? :sidebar %>

<div id="content" class="<%= !content_for?(:sidebar) ? "col-sm-12" : "col-sm-8 col-md-9" %>" data-hook>
  <%= flash_messages %>
  <%= yield %>
</div>

My Gemfile looks like this:

gem 'spree', '3.4.5'
gem 'spree_auth_devise', '~> 3.3'
gem 'spree_gateway', '~> 3.3'
gem 'sprockets-helpers', '~> 1.2.1'
gem 'vinsol_spree_themes', github: 'vinsol-spree-contrib/spree_themes', branch: 'master'

I have Ruby 2.5.1 and Rails 5.1.6
So far I've tried to do something what was suggested here, however it does not work.

I'd be happy for any help. Thank you!

[matissg]

It turns out error was related to caching, so this can be closed.