Port 443 error using Prosites

Error:
The server can not find the requested page:
alumnicreator.com/alumni-creator-pro/ (port 443)
Please forward this error screen to alumnicreator.com's WebMaster.

I get this when clicking the Register button on this site. I don't use an SSL cert on this server and have no plans to so is there a way to resolve this issue without using this port?

Any responses appreciated.