Troubleshooting SQL Server Connection Issues Print

SQL Server Connection Troubleshooting

This guide helps resolve common SQL Server connection problems on Windows hosting.

Issue 1: Cannot Connect from Application

Verify Connection String:

// Correct format for shared hosting:
Server=YOURSERVER\YOURINSTANCE;Database=YOURDBNAME;User Id=YOURUSER;Password=YOURPASSWORD;

// Or using integrated port:
Server=sql.yourhost.com,1433;Database=YOURDBNAME;User Id=YOURUSER;Password=YOURPASSWORD;

Common Connection String Mistakes:

• Using localhost instead of actual server name
• Missing instance name after backslash
• Wrong database name (case-sensitive)
• Incorrect username or password

Find Your Connection Details:

1. In Plesk, go to Websites & Domains
2. Click Databases
3. Click on your database name
4. Connection info is displayed under "Connection Information"

Issue 2: Cannot Connect from SSMS (SQL Server Management Studio)

Remote Connections:

Important: Remote SQL connections may require:

• IP address whitelisting by support
• Correct external connection details
• TCP/IP protocol enabled

SSMS Connection Settings:

• Server type: Database Engine
• Server name: Use hostname provided by your host
• Authentication: SQL Server Authentication
• Login: Your database username
• Password: Your database password

Issue 3: Login Failed Errors

"Login failed for user" Messages:

Reset Database User Password:

1. In Plesk, go to Databases
2. Click User Management
3. Select the user and change password

Issue 4: Timeout Errors

Connection Timeout:

// Increase timeout in connection string:
Server=YOURSERVER;Database=YOURDB;User Id=USER;Password=PASS;Connection Timeout=30;

Command Timeout (for long queries):

// In C#:
command.CommandTimeout = 120; // 120 seconds

// In connection string:
Command Timeout=120;

Issue 5: Database Size/Space Issues

Check Database Size in Plesk:

1. Go to Databases
2. Size is shown next to each database
3. Check against your plan's database size limit

Shrink Database (contact support):

If your database log file is large, contact support to:

• Shrink the log file (.ldf)
• Change recovery model if appropriate
• Set up log file size limits

Issue 6: Entity Framework Connection Issues

appsettings.json Configuration:

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=YOURSERVER;Database=YOURDB;User Id=USER;Password=PASS;TrustServerCertificate=True;"
  }
}

Common EF Core Issues:

• Add TrustServerCertificate=True for self-signed certs
• Add Encrypt=False if encryption not configured
• Verify migrations have been applied

Quick Troubleshooting Checklist

1. ☐ Connection string format is correct
2. ☐ Server/instance name is accurate
3. ☐ Database name exists and is spelled correctly
4. ☐ Username and password are correct
5. ☐ User has access to the specific database
6. ☐ Firewall allows connection (for remote access)
7. ☐ Database is online and not over quota