Diagnose slow API connection between website and Bullhorn

My website [login to view URL] We use Bullhorn as our applicant tracking system. Applicants search for jobs on our WordPress website and apply there. When they click the button to submit their application the website uses the Bullhorn API to attach the application and resume to the Bullhorn open position. Recently the submit process has changed from taking 3-8 seconds to almost a minute. Applicants are getting frustrated and clicking submit several times, which sends several applications to Bullhorn. The developer who created this is no longer with the company. We need a PHP expert who can look at our use of the Bullhorn API and determine why it has become so slow. Deliverables Reduce the time to submit the application and resume from the website to Bullhorn via the API back to a reasonable time - less than 10 seconds.