iframe no longer loading on page

Hello

The iframe on this page http://gelatissimo.com.au/club-gelato/ is no longer loading.

Below is the shortcode used and that has been working until the past few days:
[iframe src=”https://loyalty.gelatissimo.com.au” scrolling=”no” width=”100%” height=”600″ iframe id=”loyalty-form” style=”font-family:Aleo”]

Is this to do with the source URL or the plugin?

Any help appreciated! 🙂
Thanks

https://wordpress.org/plugins/iframe/