Increase the timeOut attribute of your connection
<add name="ConnectionString" connectionString="Data Source=;Initial Catalog=;Persist Security Info=True;User ID=sa;Password=sa@123;Connect Timeout=200" providerName="System.Data.SqlClient"/>
</connectionStrings>
OR
SqlConnection conn = new SqlConnection("ConnString");
SqlCommand comm = new SqlCommand();
comm.CommandTimeout = 120;