Can't connect from azure resource to Azure database for postgres server

Apparently, the vm is part of a vnet that a service endpoint tag Microsoft.sql was enabled.

I found this answer. To solve the problem I disabled the service endpoint and added the public IP to the Connection Security section.

I encountered the same problem.All I did was to switch Allow access to Azure services to ON .

What does the error mean?

A VM where the connection originates from is deployed to a virtual network subnet where Microsoft.Sql service endpoint is turned on. Per documentation:

If Microsoft.Sql is enabled in a subnet, it indicates that you only want to use VNet rules to connect. Non-VNet firewall rules of resources in that subnet will not work.

For connection to succeed there must be a VNet rule added on PostgreSQL side. At the time the question was asked VNet Service Endpoints for Azure Database for PostgreSQL just got to public preview so I assume it might not have been available for the OP.

Solution

As of November 2020, Service Endpoints for Postgres is GA and instead of disabling the service endpoint one can add a missing VNet rule to the PostgreSQL server instance and reference the service endpoint-enabled subnet. It can be done via Portal or Azure CLI