No deployment reaches production any more and the payments Function App will not restart

The MasterLinux course payment platform runs in the resource group rg-production: the Function App func-ml-paiements (bank callbacks, receipts), the storage account stmlproduction (queues and PDF receipts) and the student portal app-ml-portail.

An urgent fix must ship this morning: since Saturday, some payment receipts go out with a wrong amount. But the deployment pipeline has been failing since 18:30 last night, always at the same step, and the development team can no longer even restart the Function App to apply a setting by hand. The pipeline's service account sp-deploy-prod has not changed, and neither has the step's code.

You are on call, on your workstation with the Azure CLI (you are Owner of the rg-production group). The log of the last deployment is in your folder: ~/INC-3163/deploy-prod-1842.log.