We identified and resolved the issue. Apologies for the disruption.
We are seeing 502 Bad Gateway errors on the api.cal.com/v2/bookings endpoint for POST.
We will be performing scheduled maintenance on our database systems used by our web application, APIs and companion app on Saturday, February 28 from 6:00AM-8:00AM UTC. We expect systems to be unavailable for 1 minute of that window.