When trying to confirm an order that contains a voucher, if the error message “One or more items are now unavailable” pops up, as shown below…
This will mean the code has already been used so now cannot be confirmed. This will be referring to when users enter in “Custom voucher code” when adding the voucher to the order and this code has already been used…
This will even apply to vouchers that have been added and then deleted. Deleting the voucher doesn't release the code to be able to be used again so this is why using the same code for another voucher won’t be possible and the order cannot be confirmed.
To fix this, you will have to enter in a custom voucher code that hasn’t been used or leave the custom voucher code blank so that the system generates the voucher code for you.