"Key File does not exist" Error Message for Appointments+

I followed the plug in step by step process to integrate my client's google calendar with your plugin. On the final test I got an error message that the "key file did not exist". (see attached doc for screen shots. I contacted the host to see if there was a problem on the server side. There was none however the JSON file that I downloaded had a file name different from the example below the plugin field for the key file name. The key file ID on the Google site was a string of about 45 characters and numbers. Your plugin gave an example that was a string of about 20 characters and numbers while the JSON file had text before a very short string of about 9 characters and numbers. How am I to get a match on the key file with 3 different file names? Which one is the one I need and how do I get it to match?