Connector to CRM error

I was just setting up GP 2015 in a test environment and wanted it to connect to a CRM 2016 server.  When I entered the URL, etc, it told me that the CRM URL was not valid.  I did a google search - after verifying the url, of course - and found nothing.  Since the URL is valid and the CRM server is working properly, I don't understand this error.  What would cause the GP Utilities app to throw this error?

Thanks

Bert