I've been through almost all sorts of Timeout related issues with Asp.net web service development. I’d like put a check list here to remind myself and hopefully save some headache of yours. If use database, you may get ‘System.Data.SqlClient.SqlE... Timeout expired’: a: Check your connection string setting for ‘Connect Timeout’: I.e. connectionString="Data Source=SNYC14D11511;Initial Catalog=d_dbivt003;Persist Security Info=True;User ID= user;Password= Password;Connect Timeout=4200 b:Check...