API callback

Google keeps sending me this error message:"We encountered an error trying to access your server at www.cabhook.com/index.php?option=com_hik...ckout&tmpl=component -- the error we got is java.io.IOException: Error 'SSL_CERTIFICATE_ERROR' connecting to url ' www.cabhook.com/index.php?option=com_hik...ckout&tmpl=component '. "

any thoughts on whats going?i checked my called back API and it seemed fine.

Google checkout requires that the notification URL supports SSL. However, it seems that you didn't configure any SSL certificate on your website. Thus, you get these emails.
You should either setup a SSL certificate with your hosting company, or remove the callback URL from your google checkout account.

Is the callback url a specific url? I have an SSL certificate installed on my site and I'm setting up my google account now. There is a callback section for a URL, but I'm not sure which url to put in there. Is this just a https URL back to my site?

Yes it's a specific URL. You will find it in the options of the plugin as explained in the documentation:
www.hikashop.com/en/support/documentatio...form.html#additional