I noticed with my last to newsletters that not all my subscribers are listed. Been using the plugin for years and this is the first time this started happening now.
1. I create the newsletter.
2. Select the option to "Send out by Cron" and after a short while get a "page timeout" request.
When going back, I noticed that not all the subscribers numbers are different - couple hundred less.
Current PHP version: 5.6
max_execution_time 240 but increased now to 600
memory_limit 128m (Max)