title: Unable to connect AWS RDS SQL Server
body: <p>I have created a SQL Server Express instance on RDS. I have also created a security group and enabled SQL Server port range 1433 to everyone. I have also selected Yes for Publicly Accessible.</p>
  
  <p>When I try to connect from the Management Studio, I do specify server name as endpoint of the instance including port number. I did specify the master username and master password with authentication type as SQL Server authentication. </p>
  
  <p>I do get this error when connecting:</p>
  
  <blockquote>
    <p>A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 25 - Connection string is not valid) (Microsoft SQL Server, Error: 87)</p>
  </blockquote>
  
  <p>When I try to see the RDS instance log I see below messages.</p>
  
  <pre><code>2016-12-01 22:31:19.65 Logon Login failed for user 'sa'. Reason: Could not find a login matching the name provided. [CLIENT: 123.249.0.134]
  </code></pre>