Here's what our tech guy thinks:
Okay, I think I've tracked down the problem with the plugin.
It assumes that PHP has been built with an fopen() wrapper to handle SSL and https, which in our case is not true and so every outbound request using file-get-contents to https destinations will fail. If the plugin were to try using cURL instead, it would work.
So to make that part work we'll need to recompile PHP for the whole server. This will mean taking all the sites down while the new version is installed.
My response: - is this something that his plug in should be able to handle?
Well, it's making assumptions about the environment which aren't going to be true of every installation, but then so would assuming cURL was installed.
You could let him know that you think you've tracked down the problem:
That it assumes that PHP has fopen wrappers compiled in for HTTPS, which isn't the case on our install.
It'll help him a) troubleshoot others who have similar issues, b) specify the requirements for the plugin better and c) improve his error-handling.
$w = stream_get_wrappers();
echo 'openssl: ', extension_loaded ('openssl') ? 'yes':'no', "\n";
echo 'https wrapper: ', in_array('https', $w) ? 'yes':'no', "\n";
will tell him whether the installation has the required wrappers.