WHMCS: Error contacting server: Unsupported protocol


When attempting to setup billing integration with WHMCS, I receive the following error from WHMCS:

Error contacting server: Unsupported protocol:

How do I fix this?


If you are receiving this error, this indicates that you have not followed the WHMCS integration instructions in the Centova Cast installation manual. Please download that manual and follow the instructions to set up WHMCS integration.

This error message specifically means that you have entered a bare domain/subdomain name into the WHMCS "Hostname" field instead of a valid URL. Please consult the manual for further details.