Error Message
Timeout expired. The timeout period elapsed prior to completion of the operation, or the server is not responding.
Problem
Timeout errors occur on a SQL Server site when loading published documents and executing queries.
Solution
Run the following SQL on your database. Replace <Databasename> with the name of your database.
ALTER DATABASE <Databasename> SET READ_COMMITTED_SNAPSHOT ON.
If the errors persist, then increase the value for the DBCommandTimeoutSeconds setting for your site. This property is available in SmartPlant Foundation Server Manager, on the Settings node under each site node.
This issue is specific to SQL Server.