Solution: Of course right after I posted this I figured it out, I have CSF installed on WHM and I had to add the port 2199 for the outbound TCP connection after that it worked
I've contacted Centova and they seem to think it's a firewall issue, but I'm not really clear on what...
This error means that the server upon which you're running WHMCS is unable to make a connection to Centova Cast
As your Centova Cast URL appears to be valid and working, my first assumption would be that the server on which WHMCS is running has been firewalled such that it cannot make outbound connections. It is extremely common for shared web hosting providers (and even some dedicated server providers) to implement such firewall rules for perceived security reasons. I'd recommend contacting your hosting provider for assistance.
In any case, this is definitely the result of a connectivity problem between your WHMCS server and your Centova Cast server, and does not represent a problem in WHMCS or Centova Cast and the first thing you should check is that port 2199 is open on the WHMCS server.
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However the system is a CentOS Server with cPanel that is running WHCMS, so are they saying that the cPanel server also needs to have port 2199 open and is that for inbound or outbound connections? There's no custom configuration and its just a plain ol cpanel server so I would assume if custom configuration needed to be done it would have been in the documentation
So I've setup the WHMCS Module for Centova and created the server, when I go to WHMCS to list Servers I can click the link to login to Centova admin portal and that works just fine, however when it goes to create an account I get the following error:
Module Create Failed - Service ID: 2 - Error: Socket error accessing https://s1.domain.com:2199/api.php: fopen(https://s1.domain.com:2199/api.php): failed to open stream: Connection refused
When I go to the API url I just get an XML error which I've never been to the API URL so I don't know if that's what I should get anyways?
This XML file does not appear to have any style information associated with it. The document tree is shown below.
<centovacast version="3.2.12" host="s1.domain.com:2199">
<response type="error">
<message>XML root tag not found.</message>
</response>
</centovacast>
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