Jekyll::SeoTag::UrlHelper variable problem

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1

Hi,

I am trying to install Jekyll-Seo-Tag plugin. Unfortunately while building the site I get this error:

jekyll 3.5.1 | Error: uninitialized constant Jekyll::SeoTag::UrlHelper

I am rather new to Jekyll and Ruby in general, however this module seems to be loaded correctly:

module Jekyll
  class SeoTag < Liquid::Tag
    autoload :JSONLD,     "jekyll-seo-tag/json_ld"
    autoload :AuthorDrop, "jekyll-seo-tag/author_drop"
    autoload :ImageDrop,  "jekyll-seo-tag/image_drop"
    autoload :JSONLDDrop, "jekyll-seo-tag/json_ld_drop"
    autoload :UrlHelper,  "jekyll-seo-tag/url_helper"
    autoload :Drop,       "jekyll-seo-tag/drop"
    autoload :Filters,    "jekyll-seo-tag/filters"

The url_helper file looks like this:

# frozen_string_literal: true

module Jekyll
  class SeoTag
    # Mixin to share common URL-related methods between class
    module UrlHelper
      private

      # Determines if the given string is an absolute URL
      #
      # Returns true if an absolute URL.
      # Retruns false if it's a relative URL
      # Returns nil if it is not a string or can't be parsed as a URL
       def absolute_url?(string)
        return unless string
        Addressable::URI.parse(string).absolute?
      rescue Addressable::URI::InvalidURIError
        nil
      end
    end
  end
end

Source code is from https://github.com/jekyll/jekyll-seo-tag

Thanks for help!
Rafal