Issue Registering Webinar Attendees through GoToWP

We have a GoToWP premium account and have been using your plugin successfully for a few years now. However, since Citrix updated their API we have been experiencing problems. Some of these issues were solved by upgrading to Version 3.3.2 of your plugin, but unfortunately it is still not working properly.

GoToWP can sync with my GoToWebinar account and does come back with an accurate list of Webinars. However when I copy the webinar shortcode into our wordpress template page e.g. https://memoori.com/webinars/how-can-the-cloud-machine-learning-improve-the-effectiveness-of-monitoring-stations/ and try to sign up for a webinar, it does not register the user in GoToWebinar and hence user does not get a confirmation email etc.

Any ideas on what is going wrong? We are completely stuck. Has anyone reported a similar issue?