Cannot connect to SQL server named instance

I was recently assigned a bug where our product was not working with named instances of SQL server. The problem was my app can connect to default instance of a SQL server but when I tried to connect to a named instance I got generic could not connect exception from .net sql client. Problem repro s on one machine but not on another which kind a proves the problem might not be in our code. I spent some time trying to figure out the problem then I got professional help from a member of SQL team. The solution turned out to be starting the “sql browser” service which was not running. One other suggestion was to check the firewall since default and named instances uses different ports and those ports must be accessible.