Troubleshooting Here are the most common problems you can face collecting subscribers and sending newsletters from your WordPress site. The system tools A set of diagnostic tools to discover what’s going wrong. Slow email delivery When it takes ages to send a newsletter. Emails flagged as spam When your newsletters are classified as spam! Emails are not sent When emails are not received at all! Scheduler issues When Newsletter says: the scheduler is not working. Spam subscriptions How to block spam or fake subscriptions