Twitter Pixel not working in Shopify’s checkout_completed event trigger

I followed this guide to implement my Twitter pixel code, but it’s not triggering on the thank you page:

!function(e,t,n,s,u,a){e.twq||(s=e.twq=function(){s.exe?s.exe.apply(s,arguments):s.queue.push(arguments);
},s.version="1.1",s.queue=[],u=t.createElement(n),u.async=!0,u.src="https://static.ads-twitter.com/uwt.js",
a=t.getElementsByTagName(n)[0],a.parentNode.insertBefore(u,a))}(window,document,"script");

twq("config", "twitter_id");

analytics.subscribe("checkout_completed", event => {
  twq('event', 'event_id', {
    value: event.checkout.totalPrice.amount,
    currency: event.checkout.currencyCode,
    email_address: event.checkout.email || null,
  });
});

Am I doing something wrong? twitter_id and event_id are hidden for privacy/security reasons.

Should I be passing conversion_id as well for it to work? If so, how do I get it from the event object?