Need Payment Gate via Authorize.fix right away

A freelancer made some changes to my site, and now orders will not be processed through the gateway Authorize.net. The freelancer has gone missing, and so I need someone to clean up after them. Here is the error we get on checkout: Error: Couldn't resolve host '[login to view URL] Error: The transaction could not be completed Error: Failure in Processing the Payment (ps_authorize) The site is Joomla with Virtuemart. The server control panel is Plesk. The error comes with the final stage of checkout, the actual submission of the order to Auth.net.