@Vincent1662
I seem to recall you can't add a Co Host before publishing the listing? This is because I don't think the New Listing setup offers the option to add a Co Host, but that might have changed? 🤔
Be sure both you and your Co Host have your profiles completely setup and ID verified. Also be sure to send the email invite to whatever email your Co Host used on their profile. Use a laptop/desktop to send the invite and have the Co Host accept on a laptop/desktop...the App is "glitchy" and doesn't always work.