Using PDF Embed API in Filemaker Webviewer Error

I'm using PDF Embed API in Filemaker application through its webViewer object.
It's working in Filemaker Pro (a desktop version of the solution) but through web direct(web-based of the same solution) it's not working.
I have provided the correct key based on the domain shown below but it seems Embed API still consider it as not authorized

When I try to get the hostname from this webViewer object, it doesn't return anything but adobe still return error message with the correct domain name. This webViewer object is an iFrame.

Please let me know if there's any workaround for this.

Thank you.