Cannot connect to MSSQL 2008 with ip 127.0.0.1

Question

I dont have much experience with MsSql. I have no problem to connect to database by SQL management studio with SQL Server Authentication Mode on ip 127.0.0.1. But my program fails to connect. I created file connect.UDL for test connection and got this error

[DBNETLIB][ConnetionOpen (Invalid Instance()).] Invalid connection

Some information may usefull

• SQL server is on configured as Mixed Authentication Mode
• DIsabled my firewall
• Enabled all protocols (Shared Memory, Pipe names, TCP/IP, VIA)
• Using 127.0.0.1 and 1433 port for TCP/IP protocol
• Allowing remote connection on server

Can provide more information if you need. Thanks

EDIT : I deleted everything and installed SQL SERVER 2008 R2. Everything working now. Thanks all for your effort.

Answer 1

Ensure you have installed SQL Server as a "Default instance" in order to be able to connect with just the IP address or hostname. If it's a "Named instance" installation, you will need to specify the hostname and instance name to connect. (i.e. MY_HOST\MY_INSTANCE)

Check out the SQL Server Configuration Manager, and under SQL Server 2008 Services section, does the installation have the "Names instance" in brackets? - That's your named instance.