Hi, @Quentin Welcome to the Microsoft Q&A platform, and thanks for using Azure Services.
I understand that you are facing an issue while deploying Azure Postgres SQL and you also tried using CLI.
Sorry for the inconvenience caused There is an outage going on for customers creating Azure PostgreSQL flexible server. Our Product Group are actively working on it.
Existing servers are not impacted. Only PITR and new server creations are impacted.
you can also track azure service outages using the link below.
Https://Status.azure.com
Regards
Geetha