Good evening Sandra,
Thank you for writing back and providing us with your system information.
If you don’t mind, could you please send me a copy of your WordPress child theme in a .zip file link (via Dropbox or Google Drive) so that I can run some tests on my end ?
As an alternative to our built-in Try to set the status of new ticket orders to “complete” automatically option, you might want to take a look at the following snippet that you can add to your child theme’s fucntions.php to accomplish a similar goal.
The only downside is that it will set ALL WooCommerce orders to complete automatically (not just Tickets): https://docs.woothemes.com/document/automatically-complete-orders/
Let me know if that helps.
Have a great day!
Geoff B.