Field Metadata Request Returns 405
I'm trying to obtain field metadata from an AMS configuration iframe, but when making the request it sends back a payload indicating an http 405 response.
Example product request-
window.parent.postMessage({amsAction: 'product', destinationUrl: metadata.fieldMetadataEndpoint.url, method: metadata.fieldMetadataEndpoint.method}, "*")
Example response (simplified)-
payload: '<!doctype html><html lang="en"><head><title>HTTP Status 405 – Method Not Allowed</title></head><body><h1>HTTP Status 405 – Method Not Allowed</h1><hr class="line" /><p><b>Type</b> Status Report</p><p><b>Message</b> Request method 'POST' not supported</p><p><b>Description</b> The method received in the request-line is known by the origin server but not supported by the target resource.</p><hr class="line" /><h3>Responsys Interact</h3></body></html>'