Good evening Cindy and welcome back!
Thank you for reaching out to us.
We are sorry to hear about the issue you have been experiencing with the tickets not being sent to the clients.
I would love to help you with this topic.
I recently helped a customer with a very similar issue. The conclusion is that somehow the plugin that would change the order status automatically did not “perform” the exact same steps as when you manually set the order status to “complete”.
If you do not mind, this would be the first test I would suggest you to run. Temporarily deactivate the WooCommerce Order Status Control and try setting the transaction status to “Completed” manually to see if the ticket email gets sent.
Also, one of our other customers had some success with a snippet added to the WordPress theme’s functions.php: https://theeventscalendar.com/support/forums/topic/auto-send-tickets-and-auto-send/
Let me know how that goes.
Best regards,
Geoff B.