Smartsheet Add-in for GMail not appearing in my Gmail window

edited 11/08/22 in Add Ons and Integrations

I have installed the Smartsheet Add-in for Gmail, and was expecting to see a new icon at the right hand side, when I open up an email in Gmail - but I don't see any icon, so cannot open up the add-in panel and link the email to a row in a sheet.

Is there a step I have missed?

Has anyone else had this problem?