I am using SQL managment studio 2008 running on an Amazon EC2 machine. I am unable to connect to the database in my asp.net application. The EC2 instance has been set to accept connections over the SQL port. I am also able to remote the machine as well as view websites hosted on the server. Listed below is part of the connection string relating to this instance. When the program is ran and this connection string is called, it returns tcp error 0 - no return response. it just times out. <add name="ProjectServer" connectionString="Data Source=*IP ADDRESS HERE*,1433;Initial Catalog=*Catalog Name*;User ID=IP-0A6ED514\Administrator;"/> I removed the ip and the catalog name for the example, but I am sure they are correct. The only thing that I could think may cause an error, is the differences in names between the user id and the server name - the server name is ip-0A6ED514\sharepoint but the user name is ip-0A6ED514\administrator when I log into the sql server manager on the EC2 instance. A password is not used. Not sure if I would need to leave in a blank string for password - also not sure if the difference between server name and user id to log in makes a difference. Any help is appreciated. Thank you. update - when this connection string is used with out the port, i get tcp provider error 40 - when the port is in there, i get error 0 edit- the sql server is using windows authentication - does this make a difference? Usually I always use SQL server authentication