🔍 Symptoms

• “Could not connect to server”
• “Login failed for user”
• ERP software not loading
• Remote apps can’t access SQL

✔ Common Fixes

1. SQL Server: Enable TCP/IP

Open SQL Server Configuration Manager → Enable TCP/IP → Restart SQL service.

2. Open SQL port on firewall

Port 1433 must be allowed internally (never public unless secured).

3. Wrong credentials

Try logging into SSMS locally to confirm SA credentials.

4. Wrong server name

If SQL is on the same VPS → use “localhost”.

If on another desktop → use its internal IP.

5. VPN is required

External apps cannot connect without VPN unless whitelisted.