I have version 3.2 installed with the latest updates (as of last week).
 
I set up the store in TEST mode for YourPay API, and it worked great. I then switched the payment system to LIVE. Now, when someone attempts to pay, they get an error of 'Empty response from gateway. Please check your settings.'
 
If I switch the payment system back to GOOD of DECLINE, I still get the same error.
 
The odd thing, is that I have a test server installed and as far as I can tell, it has the same setting for YourPay, and it works fine.
 
Can anyone tell me what would cause this type of error to occur, and what would need to be done to debug this?