Scope
Unable to open Pay Now URL
Blank page while opening Pay Now link
Pay Now URL is used to initiate payment collection from custom
This can happen is because smart routing is not configured for the currency of the invoice which is being paid for using this link.
In order to accept payments, you would need to configure smart routing rules in your payment gateway for the currency.
Check the currency of the invoice and confirm if the smart routing settings have been configured for the same currency.
You can check this under Settings->Configure Chargebee->Payment Gateways->Smart Routing
Once configured the Pay Now link shall work fine. You can read more about Smart Routing here.