drupal_add_js() does not add .js file from libraries folder
That seems apply to your issue :


  This problem occurs because the path to library is often incorrectly
  set as

libraries\colorbox\jquery.colorbox-min.js

  
  The solution should be to correct the path. You need to place the
  whole Colorbox plugin directory after unpacking it in
  sites/all/libraries This means the path should look like

sites/all/libraries/colorbox/colorbox/jquery.colorbox-min.js



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