While doing DNN 9 Installation on Windows 10 Machine having Sql Server 2017, i get this error - connection to the DB Failed.

The connection strings are as follows -

<add name="SiteSqlServer" connectionString="server=(local);database=xx;uid=yy;pwd=zz;" providerName="System.Data.SqlClient" />

<add name="localSqlServer" connectionString="Data Source=.\sqlexpress;Integrated security=sspi; attachdbfilename = |DataDirectory|aspnet.mdf; User instance = true" providerName="System.Data.SqlClient" />

Where am i going wrong? Any help appreciated!