Also getting "API did not return Success message"
Can not get the front end or back end working.
It looks like Mozilla didn't provide the root authority cert with the version of PHP (7.3) we are using on IIS.
Take a look at this https://martinsblog.dk/windows-iis-with-php-curl-60-ssl-certificate-problem-unable-to-get-local-issuer-certificate/
or
Curl is required in php.ini: curl.cainfo="C:\Program Files (x86)\PHP\v7.3\extras\ssl\cacert.pem"