PhantomJS failing on remote ajax field check - ajax

Question

I developed a script to complete & submit a remote form via PhantomJS (version 2.1). For testing I built a local approximation of the remote form which included an ajax field check upon input (so, you enter an email address in the email field, and after a second it checks to see if it's a valid input). My phantom script fills out the fields, waits a few seconds for an error to be thrown, and then carries on to submit the form if everything looks okay. This all worked just fine with everything running on localhost.
However, as soon as I switch to making the call to the remote webpage (which is a third-party site; I have no access to make changes to it), it fails when the remote page performs the ajax check on fields. I have the following onResourceError function:
page.onResourceError = function(resourceError) {
system.stderr.writeLine('= onResourceError()');
system.stderr.writeLine(' - unable to load url: "' + resourceError.url + '"');
system.stderr.writeLine(' - error code: ' + resourceError.errorCode + ', description: ' + resourceError.errorString );
};
...and if I run the following line (in a Windows command prompt):
phantomjs.exe form-process.js "https://contact.site.com/auth/form?params=that&are=always&the=same" "clarence#email.com"
I get the following error:
https://contact.site.com/ajax/email-check?email=clarence#email.com"
- error code: 302,
- description: Error downloading "https://contact.site.com/ajax/email-check?email=clarence#email.com"
- server replied: Bad request
I am running this from a local environment but with no SSL certificate installed, so I assumed (based on the description of the 302 error code: the requested operation is invalid for this protocol) that it was a cross-protocol issue. But running the phantomJS line with any combination of --ssl-protocol=any, --ignore-ssl-errors=yes or --web-security=false yields the same results.
I may be misunderstanding these modes for phantomJS, but I assumed that --ssl-protocol=any would dismiss this issue, but would I still need to have a local SSL cert to get this to work? Or is there another issue here?