National Pension System Trust — Payment Gateway error while registering for NPS account

Website:

enps.nsdl.com/eNPS/NationalPensionSystem.html

Hello
I am getting an error while registering for NPS account. Following is the error message.

Error message: The response from the Payment Gateway for the payment attempt against this acknowledgement number is awaited. We request you to wait for the re-try of payment process for registration in NPS #