Changing Google EventReservation markup list

We would like to send the event reservation markup along with our order confirmation email. The schema was implemented using JSON + LD and in accordance with the requirements set out in the google reference document for event reservations .

We completed the form required by Google and sent one of our confirmation emails to the provided email address with the markup data. In response, we were told that "the scheme was empty ." When trying to request additional information, we received an unanswered message from the address that contacted us.

I am adding a link to the html of the email sent along with the form confirmation emails with markup data here . Our sent email content is base64 encoded, could this be the reason for the email rejection? If not, what other actions can we take to get the event reservation markup displayed in our emails?