emmi4

It turns out that the Subtotal is calculated as the price of the item with VAT (21%) + VAT on delivery. For example, the price of the product is 80,55 incl. VAT, the delivery is 3,50 incl. VAT (VAT 0,61), then the Subtotal shows 81,16 (80,55 + 0,61).

Now new update appeared and everything works again! Thank you!

Yes

Plugin Version 1.2.106

I activated the plugin and tried again, created a new order and still no confirmation of the order is sent to either the admin email or the customer email. The same error appears when performing a manual resend order notification.

I deactivated the plugin and e-mails are sent as they should

After I roll back to 6.5 version, Internal Server Error still occurs.
After I roll back to 6.4.1 version, everything works correct, without any error!