Tested the API but could not find a log to check for any issue in c:\ProgramData\Screening Deployed\logs?
In the ProgramData\... look for the ..\Apache Tomcat 7.0.xx ME3\logs folder
Look in localhost_access_log.xxxx-xx-xx.txt & localhost.xxxx-xx-xx.log
localhost_access_log.2016-07-15.txt
This will give you a transcript of the API commands and responses
localhost2016-07-14log.txt
This will give you a log of the Apache Tomcat ME3 service and the matching engine application environment. (Note: I forced an error [bad path] in the attached log to show a example of an error message)