I am using opencart 2.3.x due to a recent upgrade, all the new incoming orders are ending up in cancelled orders and can be found in the "missing orders" only and nothing is showing in the admin error log.
This applies to all my payment methods I have (bank transfer, paypal standard, cash on delivery), and all the order_status_id = 0 in the database.
Desperatly need some help with this.
If all of that settings are correct, looks like your customers did not finished their purchases.
Because the moment they reach the final page in the checkout, the order is created with the status = 0.
The status will then be changed only after confirmation.