WHMCS: No suitable wrapper could be found

Question:

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

Error: Socket error accessing https://example.com/api.php: fopen(https://example.com/api.php) [function.fopen]: failed to open stream: no suitable wrapper could be found

How do I fix this?

Answer:

This can occur for any of the following reasons. In declining order of likelihood:

  1. You have disabled the allow_url_fopen option in your php.ini file on your WHMCS server. Ensure that you have set allow_url_fopen=On in php.ini to fix this issue.

  2. You are using an https:// URL to Centova Cast, but your PHP installation on your WHMCS server was built without SSL support. PHP would need to be recompiled to fix this.

  3. You have built PHP on your WHMCS server with the --with-curlwrappers option. This is an experimental feature that has a number of known bugs that can interfere with PHP's built-in ability to access remote URLs via HTTP. If all else fails, you may need to recompile PHP without --with-curlwrappers to fix this issue.