"login Failed For User" When Specifying Default Port

Trying to debug a customer's connection problem when they try specifying the SQL Server port. Reproducing the issue locally I checked and my server runs under the default 1433 port

Solution 1:

If you are using SQL Server Express and a named instance then the port will not be 1433 but rather a dynamically assigned port.

See this article, scroll down to the section 'Ports used by SQL Server' and look for 'SQL Server named instances in the default configuration'.

http://msdn.microsoft.com/en-us/library/cc646023.aspx

I don't know if you can assign specific ports to SQL Server Express instances. If so, that is what you would need to do, and specify that port in your connection string. If it is not possible to assign a specific port to a to SQL Server Express named instance then you would have to stick with specifying the instance name, without a port.