network path could not be found

Question

i have install SQL server SQLExpress 2012 in my local laptop. my problem is everytime i run an asp .net c# page, i get error 'System.ComponentModel.Win32Exception: The network path was not found'. i've check everthing, firewall, connection string, SQL Server configuration management but nothing works.. the connection is not stable..sometimes it can connect, sometimes it cannot connect.. how can i fix it.. below are my 2 connection string that i have tried in my web.config. tq so much...

 

<connectionStrings>

<!--<add name="ecevasConnectionString1" connectionString="Data Source=.\SQLEXPRESS;Initial Catalog=LocalEcevas;Persist Security Info=True;User ID=sa;Password=XXX" providerName="System.Data.SqlClient" />

 

<add name="ecevasConnectionString1" connectionString="Data Source=1LocalEcevas;Initial Catalog=LocalEcevas;Integrated Security=False;User ID=sa;Password=XXX" providerName="System.Data.SqlClient" />

</connectionStrings>