Problem using Zapier to link Airtable + Webflow CMS

I’m trying to create a Zap so that whenever a new record gets created in Airtable an item is created in the corresponding Collection in Webflow CMS.

I keep running into errors and I don’t know what is causing it. Here’s one example:

It may have something to do with having to pass a slug, which is a compulsory field. I’ve tried:

leaving that field blank (i.e. unmatched to any Airtable field)
passing lowercase words only e.g. ‘taiwan’ or ‘iceland’
passing a URL e.g. http://tripsha2.webflow.io/trips/taiwan-trip
passing a URL without http://

and changing the Airtable field type between short text and URL. Nothing seems to work! Can anyone shed light on why this might be happening?