WHMCS: Order Accept Encountered Problems- Curl error: couldn't connect to host Url

For the past four hours I have been trying to configure TCAdmin to work with whmcs. I set up the server in the server setting of WHMCS and added all the configurable options. I got my first demo order and when I select "Accept Order" I get this error:

Order Accept Encountered Problems
Curl error: couldn't connect to host Url:

[To see links please register here]

For some reason WHMCS can't connect, but when I connect I get this: "Visit

[To see links please register here]

for help". I tried that. Still no luck.

So I went into my server, found the billingapi.aspx file and it said this:
This is a marker file generated by the precompilation tool, and should not be deleted!"

Does anyone have any suggestions or solutions? All help is appreciated :)

-Max