How to use port 5433 with Azure managed postgres
You can not change the port that Azure Database for PostgreSQL server uses. Connections to your Azure Database for PostgreSQL server communicate over port 5432. When you try to connect from within a corporate network, outbound traffic over port 5432 might not be allowed by your network's firewall. If so, you can't connect to your server unless your IT department opens port 5432.

If you truly need to use port 5433 you can install PostgreSQL on an Azure VM (IaaS).