The wp-defender or Defender plugins is giving this error
Warning: include(/home/yourpathtopublic_html/public_html/custom-wp-content-url/plugins/wp-defender/app/component/class-wd-dir-tree.php): failed to open stream: No such file or directory in /home/yourpathtopublic_html/public_html/custom-plugin-url/wp-defender/app/class-wd-utils.php on line 97
Yes, I modified the plugin directory of wordpress to something else than wp-content
For quickfix, you should change the line 97 of Defender plugin located in your-plugin-directory/wp-defender/app/class-wd-utils.php which like this
include WP_CONTENT_DIR . '/plugins/wp-defender/app/component/class-wd-dir-tree.php';
include WP_PLUGIN_DIR . '/wp-defender/app/component/class-wd-dir-tree.php';
so it will give the right url whether you modified plugin directory or not
I hope WPMUDEV will fix this in the next update of Defender plugin.