Hosted pay page isn't loading

I've created a hosted pay page and it was working fine for the last few months. All of a sudden the when the user inputs there info, total charge amount and hits submit It doesn't load the hosted paypage anymore. It goes to a blank page at the address https://www3.moneris.com/HPPDP/index.php

Some trouble shooting I've done:

1. Generated a new key to see if that would fix the issue

2. Disable plugins to if there's conflicts happening

 

Please let me know if theres anything else I can try.

Thanks