1. Use TLS 1.2 : You must use version 1.2 of the TLS protocol to secure your data communication.
2. SQL Server Browser Settings : For SQL Server Browser to work, port 1433 on your server must be open.
3. Allow External IPs : Your server must allow external IP addresses. If you only want to allow certain IPs, just allow the platform's IP address.
4. Test Connection String: Test Connection String over an external network first. This test verifies that your connection is accessible from the outside world.
5. SQL Configuration Manager Settings: In SQL Configuration Manager, enable the "TCP/IP" protocol in the "Client Protocols" section. Also, the "Named Pipes" protocol must be enabled. If these two protocols are not enabled and were enabled later, you will need to restart SQL Server for the changes to take effect.
