When I am uploading and activating the add on to my site, the site going down. There is a an error that says
The site encountered a problem that it cannot recover from. Please use the following information to try to resolve the problem.
Fatal Error: Class 'IT_Exchange_Product_Feature_Abstract' not found in /opt/bitnami/apps/wordpress/htdocs/wp-content/plugins/exchange-addon-quantity-discounts/class.quantity-discounts.php on line 9
The iThemes Exchange - Quantity Discounts plugin code created an error that caused PHP execution to fail.
The code tried to use a PHP class that doesn't exist (IT_Exchange_Product_Feature_Abstract). This type of error is typically caused by a simple typo (WP_error rather than WP_Error), by trying to use a class that is provided by a plugin when that plugin is not activated, by trying to use a class before it is ready (such as trying to use a class before the code that creates it has run), or by trying to use a class that no longer exists (the class may have been removed from WordPress core or the plugin/theme that previously supplied it).
- Invalid code modifications can cause this problem. If you have made any modifications to the plugin, remove them and try to load the site again.
- It is possible that this plugin's code is out of date and that an upgrade is available. Check with the plugin's author to see if an upgrade is available.
- There may be a conflict with another plugin running on the site. Try upgrading the other plugins on the site. A plugin conflict can be ruled out by deactivating all the other active plugins on the site and checking to see if the error still occurs.
- The iThemes Exchange - Quantity Discounts plugin may not have been fully uploaded. Uploading the plugin again could fix the issue. Important: If you do this, you will lose any modifications made to the plugin.
Could you please help me here and explain what the issue is?