Unable to accept order in WHMCS

I've performed all the configuration setup required on my Wordpress site and WHMCS. The payment selected is Paypal. Still figuring how I can enable multi payment mode such as Paypal, Bank, etc.

On testing, I can only select Paypal and complete the form without making payment. I then go back to my WHMC order screen and attempted to accept the order but error occured. Going to the system activity log, the error are as follows:
Module Create Failed - Service ID: 2 - Error: Connection Error: 6 - Couldn't resolve host 'http'

Appreciate your advise. Thanks!