The load failed for the <script> with source "http: // localhost:3000/assets/tinymce/themes/modern/ theme.js".

[Moriort]

Ruby version: ruby 2.5.3p105 (2018-10-18 revision 65156) [i686-linux]
Rails version: Rails 5.2.4.1

I receive this message in the browser console and the textearea does not appear.

The load failed for the <script> with source "http: // localhost:3000/assets/tinymce/themes/modern/ theme.js".

in application.js

//= require tinymce

$(document).ready(function() {
  tinyMCE.init({
    selector: 'textarea',
    resize: 'none',
    plugins: 'advlist lists code autolink link image charmap print preview help table textcolor colorpicker',
    toolbar: 'numlist bullist undo redo | bold italic underline | code | forecolor backcolor',
    table_default_styles: {
      'border-collapsed': 'collapse',
      'width': '100%'
    },
    table_responsive_width: true,
    language: 'es'
  });
});

In form.html.erb
<%= form.text_area :mensaje %>

Before this did not happen, from one moment to another it stopped working and there are no more messages that can help me.

I received the same message using the activeadmin.

[affkjuhyt]

I same problem for Tinymce on ROR