@twisted1919 I had a look and found we're not the only ones who've had issues with PCTNL. It seems like something is really wrong either with this function or the way mailwizz works on different servers. It would be at least helpful if you could share information as for proper implementation and what kind of a server is ideal for running mailwizz. By the way, I noticed another pattern. Whenever I start the campaigns, some have the Processing status and others have the Sending status. They almost never change. The Processing keep processing and the Sending keep sending. But, in the delivery logs, it is only the Processing that are sending the emails. The Sending campaigns are absent in the delivery logs.