There can be multiple reasons behind this depending on the conditions you defined for the rule.
Please check the validity of the voucher or if you have applied any restriction on room type or customer group.
Also, check how total vouchers and per person vouchers are available.
Still, you face the issue then please raise a ticket. https://webkul.uvdesk.com/en/customer/create-ticket/
@frankofem Every version of QloApps provided the full booking process functionalities including payments.
A customer can do bookings and pay for it.
By default, we have enabled Pay by check and Bankwire payment methods in QloApps.
If you want to take online payments then you will need a payment gateway. We have integrated PayPal Payment gateway with QloApps by default but if you need any other payment gateway of your choice then we can also integrate as well.
And it will be a Paid Service.
I have already answered a query on this forum regarding Payment Gateways. Please follow this link: http://bit.ly/2B5tjew
Now the regarding the currency,
Yes, you can use Naira as your currency in QloApps.
Just go the Localization Section and install Nigeria Localization Pack.
Nigerian taxes, languages and currency can be installed in this pack.