sql connection server client in windwos application

Question

I use same window application in server and. server work fine but client working but sql database in server machine, client machine not access or connect server machine database. this server machine sql connection string -

<add name="ConnectionStrings"

connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Soft SolutionASD\Soft Solution\Data\MediDataNew.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True" providerName="System.Data.SqlClient"/>

plz suggest me how to connect client machine to server machine database.