2. Make sure that your WordPress cron is running. We often see customers with DISABLE_WP_CRON constant defined in their wp-config.php file but nothing else running the cron or a server cron which isn't working. If need be, check your server cron or remove that DISABLE_WP_CRON from wp-config.php temporarily.
3. Check for errors in the queue under Newsletters > Email Queue? If the email settings aren't working as they are supposed to or the process cannot finish, the transient may become stuck. Turn on debugging under Newsletters > Configuration then go back to Newsletters > Email Queue and click "Run Now" after doing step #1 above to see if there are any PHP fatal errors? A parse error could indicate an outdated version of PHP.
That should resolve it and then the emails can continue going out.
Comments
For the "Process is already running" message, do this to solve the problem:
1. Check if there is a stuck transient. You can install the Transients Manager plugin to delete all transients with
wp_queue_process.... Get the plugin here: https://wordpress.org/plugins/transients-manager/2. Make sure that your WordPress cron is running. We often see customers with
DISABLE_WP_CRONconstant defined in theirwp-config.phpfile but nothing else running the cron or a server cron which isn't working. If need be, check your server cron or remove thatDISABLE_WP_CRONfromwp-config.phptemporarily.3. Check for errors in the queue under Newsletters > Email Queue? If the email settings aren't working as they are supposed to or the process cannot finish, the transient may become stuck. Turn on debugging under Newsletters > Configuration then go back to Newsletters > Email Queue and click "Run Now" after doing step #1 above to see if there are any PHP fatal errors? A parse error could indicate an outdated version of PHP.
That should resolve it and then the emails can continue going out.