You need a Partner Id
The iFrame will only work if you specify apartnerId value.
You can use the demo partner id to test things out on localhost or 0.0.0.0, but if you want to actually deploy the iFrame on your site, we’ll need to set up a real partner id for you. This unique id is what unlocks integration on your domains (we’ll ask you your production and development domains to whitelist on our side).
We can also set up a custom color theme to better match your brand, it will be
triggered by your partner id.