How to troubleshoot missing emails

Starting with version 3.9, email digests are sent asynchronously, using the WP_Background_Process library. Both immediate emails ("All Email") and daily/weekly digests are sent using this system. If users are not receiving notifications, here's where to begin debugging:

• Are users properly subscribed to activity in the group? Check the wp_bpges_subscriptions table.
• Are activity items being queued properly in wp_bpges_queued_items?
• Background processes depend on the server's ability to ping itself, via a self-request to {server}/wp-admin/admin-ajax.php. Is your server configured to prevent these types of request? Check your access logs for potential issues.
• Enable logging by placing the following in your wp-config.php file: define( 'BPGES_DEBUG', true );. By default, the log file is called bpges-debug.log, and is in your primary uploads directory (usually wp-content/uploads). Customize the log location using the BPGES_DEBUG_LOG_PATH constant.
• Is WP's "cron" system disabled? BPGES needs this system in order for async emails to be sent.