Chifaa RDV: medical appointment booking has returned 500 errors since version 3.0

Chifaa RDV is a fictional platform for booking appointments with doctors and clinics in Marrakesh and Agadir (www.chifaa-rdv.ma). The API runs on ECS Fargate (service chifaa-rdv-api, autoscaling from 4 to 16 tasks) and uses an RDS for MySQL 8.0 database chifaa-rdv-prod.

Version 3.0 (new time-slot engine) went out at 09:02. Since 09:05, about a third of bookings fail with a 500 error, especially during practice opening hours. The CTO suggests “moving the database to an instance twice as big”.

You are the on-call cloud engineer, with the AWS CLI v2 (region eu-west-3) and read-only mysql access from the bastion.