I use Calendly for work and have been having a lot of people no-show on me and, upon digging further, it seems a Google setting with Gmail is blocking unknown calendar invites from appearing on your calendar.

Google seems might have auto-opted in people to this new setting that hides calendar invites from unknown senders. Supposedly, it's to combat spam, but filtering things out like a Calendly event has caused people issues with missing appointments.

In your google calendar settings, you'll want to update this highlighted part: https://i.imgur.com/5A8GKLL_d.webp?maxwidth=760&fidelity=grand

Twitter thread on it: https://twitter.com/michaelglena/status/1655946790167007232