Hi Phil,

Just made it into SparkPost and am running tests.

Turns out that this issue is related to SparkPost EU support. SparkPostEU runs on a different API server. I just coded in support and loaded my changes into your site. (For everyone else support will be available in the next Inbound PRO release.) SparkPost EU servers must be relatively new. First time I’ve seen the option.

Everything seems to be good now and the API connection working.

There still is one problem when I try running an email test. The CURL procedure seems to be failing when we’re using it to connect to an email preview page to render it for it’s HTML.

To be honest I am not sure why. I have a gut feeling it it security related. I ran a test as a SparkPost EU user from my local and made sure the coding was correct. There was no problem there.

I found this this article that may suggest it was a server setting https://www.samuelaguilera.com/post/curl-error-28-wordpress

I tried the advice of setting this piece of code into play:

add_filter( 'https_local_ssl_verify', '__return_true' );

But it did not work. At this point it could not hurt to know a little more about your host and possibly open a support ticket with them asking if there are any rules that would prevent the site from making a CURL call to itself, and providing an error that looks like this:

Inbound PRO had an error loading this email variation. Please check the debug details below for clues to solving.
Variation Destination: https://www.yourwebsitedomain.co.uk/mail/2647/?inbvid=0&disable_shortcodes=1

WP_Error Object
(
    [errors] => Array
        (
            [http_request_failed] => Array
                (
                    [0] => cURL error 28: Operation timed out after 10001 milliseconds with 0 out of 0 bytes received
                )

        )

    [error_data] => Array
        (
        )

)