Klaviyo form loading very slowly or not at all

I have a Shopify site and have tried embedding a Klaviyo form in this landing page - https://2xedge.com/pages/black-friday - in two ways:

1. using the Shopify “app embed” section in the page template
2. taking the code snippet provided by Klaviyo and pasting it into a “custom liquid” section in the page template. 

Clearing my browser cache, using incognito windows, and testing on various devices, 50% of the time the Klaviyo form embedded in the page doesn’t load at all. The other 50% of the time it takes 30 to 120 seconds (2 minutes) to appear.

The page loads fast - it gets a Page Speed Insights score of 98 on mobile and 100 on desktop. 

What do I need to do to get this form to load 100% of the time, and to load quickly. I get that there will likely be a delay and a few seconds would be acceptable - not minutes.

Thanks for any/all help!