Hi,

when I check your page I see

(index):253 Advanced iframe configuration error: The configuration of "resize_on_element_resize" is invalid. The specified element "sc-d5ecb649-0 jsbouZ" could not be found or accessed. Please check your configuration.

Please try
resize_on_element_resize=".elementor-1245" 

resize on element resize is the best way. You html is completely rendered dynamically. So if the element cannot be found the external workaround should be used as then the logic is inside the iframe. 

The external workaround has also the advantage that you can debug. So maybe you simply add the ai_external.js to the page in the iframe

Best regards, Michael