Transaction Not Completed Timed Out response

I downloaded the new PHP API and tried running a couple of the test scripts (TestPurchase.php and TestPurchase-Efraud.php) and yesterday both of these seemed to be working on both my localhost and live servers.

But today, whenever I had tried running either of these I keep getting back the response message "Transaction Not Completed Timed Out" and all other fields are returned a null.

Any ideas on why these test scripts would have stopped working all of a sudden? Until I can get the tests working I cannot continue with the production code.

 

Thanks