Ruby Thin Server ActionView::Template Error

I'm currently stumped on an error when pushing my project to a live environment on Amazon Web Services and then accessing the domain.

ActionView::Template::Error (Command 'java -jar /home/ubuntu/.rvm/gems/ruby-2.1.10@silk/gems/yui-compressor-0.12.0/lib/yui/../yuicompressor-2.4.8.jar --type css --charset utf-8 /tmp/yui_compress20190221-3152-1wh64vu' returned non-zero exit status
  (in /home/ubuntu/ssc-staging/app/assets/stylesheets/application.css)):
    7:     %meta{:'http-equiv' => "X-UA-Compatible", :content => "IE=edge,chrome=1"}/
    8:     %meta{:name => 'viewport', :content => 'width=device-width, initial-scale=1.0'}/
    9:     = favicon_helper
    10:     = stylesheet_link_tag 'application', "//ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css"
    11:     = yield :css
    12:     = javascript_include_tag 'application'
    13:     = yield :js
  app/views/layouts/application.html.haml:10:in `_app_views_layouts_application_html_haml___4483641441858119908_47087558678120'

The above error comes with this page.

The error specifically comes from line 10, being a stylesheet link tag to jquery-ui.css. If I delete this line my project will load albeit without css styling. If I run the project locally it works fine.

I haven't made any changes to the 'application.html.haml' file. If I do a rollback and deploy on previous functioning commits the same error appears even though these versions of the build worked without a hitch.

Ruby web server is Thin working in conjunction with Nginx.