** This issue has been fixed in version 4.0.1 and above.
Version 4 is available on ThemeForest, unfortunately on some user’s website "Internal server error" happen, that’s because of incompatibility of functions that we used on Massive Dynamic with old version of PHP ( prior to 5.6 )
To solve this issue please follow these steps:
1 - Ask your host administrator to update your website PHP to at least version 5.6
2 - Till that update happens please download attached files ( at bottom of current page ) and move it to
scripts.php >> wp-content/themes/massive-dynamic/lib
utilities.php >> wp-content/themes/massive-dynamic/lib
customizer-loader.php >> wp-content/themes/massive-dynamic/lib
shortcode-sidebar.php >> wp-content/themes/massive-dynamic/lib/mbuilder/templates
Note: This issue only happen on 4.0 version, in next version it will be fixed
Hope it helps.