Bouregreg Immobilier: the agents' software can no longer open the database

Bouregreg Immobilier, a Rabat real-estate agency (offices in Agdal and Hay Riad), manages its mandates, viewings and contracts with in-house software, bouregreg-crm, installed on a Linux server at the Agdal office. The data lives in an Azure SQL Database: sql-bouregreg.database.windows.net, database crm_biens (resource group rg-bouregreg-data, francecentral).

Yesterday afternoon, the ISP replaced the office's fibre box (upgrade to a faster plan). Everything seemed to work: Internet, phone, e-mail.

This morning, none of the twelve agents can open a single record; three preliminary sale agreements are due to be signed before noon. You are logged on to the office server, with the Azure CLI and sqlcmd.