<add key="SqlConnectionString" value="Data Source=MINTU\SQLEXPRESS\SQLEXPRESS;Initial Catalog=EmiInventory;Integrated Security=False;user=sa;password=database" />
change your connectionstring. your datasource is wrong. MINTU\SQLEXPRESS\SQLEXPRESS reemove one of this SQLEXPRESS and use this
<add key="SqlConnectionString" value="Data Source=MINTU\SQLEXPRESS;Initial Catalog=EmiInventory;Integrated Security=False;user=sa;password=database" />